Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0004152 dihydroorotate dehydrogenase activity	IBA GO_REF:0000033	ACCEPT	Summary: IBA annotation for the generic dihydroorotate dehydrogenase activity. This is the correct enzyme activity for DHODH, though GO:0106430 (quinone-using) is more specific. Human DHODH is a class 2 enzyme that uses ubiquinone as electron acceptor (PMID:8925840, UniProt Q02127 EC 1.3.5.2). IBA annotations are phylogenetically informed and represent a good baseline. Reason: Correct core molecular function. While GO:0106430 (dihydroorotate dehydrogenase (quinone) activity) is more specific, this generic term is also accurate as DHODH does catalyze oxidation of dihydroorotate to orotate. The IBA annotation is phylogenetically sound and consistent with the literature. Supporting Evidence: PMID:8925840 Human mitochondrial dihydroorotate dehydrogenase (the fourth enzyme of pyrimidine de novo synthesis) has been overproduced by means of a recombinant baculovirus UniProt:Q02127 Catalyzes the conversion of dihydroorotate to orotate with quinone as electron acceptor
GO:0005743 mitochondrial inner membrane	IBA GO_REF:0000033	ACCEPT	Summary: IBA annotation for mitochondrial inner membrane localization. This is the correct and specific localization for human DHODH. The enzyme is embedded in the inner membrane with its ubiquinone-binding tunnel facing the membrane lipid bilayer (Zhou et al. 2021, PMID:8925840). Reason: Correct core cellular component. DHODH is specifically localized to the mitochondrial inner membrane as a single-pass membrane protein with an uncleaved transit peptide required for targeting and proper membrane integration (UniProt Q02127). Supporting Evidence: PMID:8925840 The targeting of the recombinant protein to the mitochondria of the insect cells was verified UniProt:Q02127 Mitochondrion inner membrane
GO:0006207 'de novo' pyrimidine nucleobase biosynthetic process	IBA GO_REF:0000033	ACCEPT	Summary: IBA annotation for de novo pyrimidine nucleobase biosynthesis. DHODH catalyzes the fourth step in de novo pyrimidine biosynthesis, converting dihydroorotate to orotate which is subsequently converted to UMP. This is a core biological process for the enzyme. Reason: Core biological process. DHODH is essential for de novo pyrimidine biosynthesis, as demonstrated by Miller syndrome where biallelic loss-of-function mutations cause severe developmental defects due to impaired pyrimidine synthesis. Supporting Evidence: PMID:8925840 Human mitochondrial dihydroorotate dehydrogenase (the fourth enzyme of pyrimidine de novo synthesis) UniProt:Q02127 Pyrimidine metabolism; UMP biosynthesis via de novo pathway
GO:0009220 pyrimidine ribonucleotide biosynthetic process	IBA GO_REF:0000033	ACCEPT	Summary: IBA annotation for pyrimidine ribonucleotide biosynthesis. DHODH produces orotate which is the precursor for UMP, CTP, and other pyrimidine ribonucleotides. This is a core biological process for the enzyme. Reason: Core biological process. DHODH inhibition depletes UMP/UTP and impairs ribosome biogenesis and mRNA translation, demonstrating its essential role in pyrimidine ribonucleotide biosynthesis. Supporting Evidence: UniProt:Q02127 UMP biosynthesis via de novo pathway
GO:0004152 dihydroorotate dehydrogenase activity	IEA GO_REF:0000120	ACCEPT	Summary: IEA annotation via combined automated methods. Correctly identifies the core enzyme activity. Duplicate of the IBA annotation but acceptable as independent computational evidence. Reason: Correct molecular function annotation. This duplicates the IBA annotation which is fine - multiple evidence codes supporting the same term strengthens confidence. Supporting Evidence: UniProt:Q02127 EC=1.3.5.2 {ECO:0000269\|PubMed:8925840}
GO:0005737 cytoplasm	IEA GO_REF:0000002	REMOVE	Summary: IEA annotation mapping cytoplasm from InterPro. This is overly general and misleading for DHODH, which is specifically localized to the mitochondrial inner membrane, not distributed throughout the cytoplasm. Reason: This annotation is misleading. While technically mitochondria are in the cytoplasm, GO:0005737 (cytoplasm) implies cytosolic localization which is incorrect. DHODH is an integral inner mitochondrial membrane protein. The more specific term GO:0005743 (mitochondrial inner membrane) is already annotated and is the appropriate localization term. Supporting Evidence: UniProt:Q02127 Mitochondrion inner membrane
GO:0005743 mitochondrial inner membrane	IEA GO_REF:0000044	ACCEPT	Summary: IEA annotation from UniProtKB/Swiss-Prot subcellular location mapping. Correctly identifies the specific localization of DHODH. Duplicate of IBA annotation with different evidence source. Reason: Correct localization annotation. Consistent with experimental evidence from PMID:10727948 cited in UniProt for subcellular location. Supporting Evidence: UniProt:Q02127 Mitochondrion inner membrane
GO:0006207 'de novo' pyrimidine nucleobase biosynthetic process	IEA GO_REF:0000002	ACCEPT	Summary: IEA annotation from InterPro mapping. Correctly identifies the core biological process. Duplicate of IBA annotation with different evidence. Reason: Correct biological process annotation with independent computational evidence supporting the IBA annotation. Supporting Evidence: UniProt:Q02127 Pyrimidine metabolism; UMP biosynthesis via de novo pathway
GO:0006221 pyrimidine nucleotide biosynthetic process	IEA GO_REF:0000043	ACCEPT	Summary: IEA annotation from UniProt keyword mapping. This is the parent term of GO:0009220 (pyrimidine ribonucleotide biosynthetic process) and is correct but less specific. Reason: Correct but less specific than already-annotated child terms. Acceptable as part of the annotation hierarchy - provides a broader grouping. Supporting Evidence: UniProt:Q02127 Pyrimidine biosynthesis
GO:0016020 membrane	IEA GO_REF:0000002	MARK AS OVER ANNOTATED	Summary: IEA annotation for membrane localization. Too general - more specific term GO:0005743 (mitochondrial inner membrane) is already annotated. Reason: While technically correct (DHODH is a membrane protein), this term is uninformatively general. The specific localization GO:0005743 (mitochondrial inner membrane) is already correctly annotated. This adds no additional information and clutters the annotation set. Supporting Evidence: UniProt:Q02127 Single-pass membrane protein
GO:0016491 oxidoreductase activity	IEA GO_REF:0000043	MARK AS OVER ANNOTATED	Summary: IEA annotation for generic oxidoreductase activity. Too general - more specific terms (GO:0004152 or GO:0106430) are already annotated. Reason: This is the root term for oxidoreductase activities and is too general to be informative. The specific enzyme activity GO:0004152/GO:0106430 is already annotated. This term adds no useful information about the specific function of DHODH. Supporting Evidence: UniProt:Q02127 EC=1.3.5.2 {ECO:0000269\|PubMed:8925840}
GO:0016627 oxidoreductase activity, acting on the CH-CH group of donors	IEA GO_REF:0000002	MARK AS OVER ANNOTATED	Summary: IEA annotation for oxidoreductase activity on CH-CH bonds. While this describes the chemistry of the reaction (dihydroorotate has a CH-CH bond that is oxidized), it is less informative than the specific enzyme activity terms already annotated. Reason: Correct but uninformatively general. The specific enzyme activity GO:0106430 (dihydroorotate dehydrogenase (quinone) activity) or GO:0004152 provides much more useful information. This intermediate-level term adds little value. Supporting Evidence: UniProt:Q02127 Reaction=(S)-dihydroorotate + a quinone = orotate + a quinol
GO:0106430 dihydroorotate dehydrogenase (quinone) activity	IEA GO_REF:0000120	ACCEPT	Summary: IEA annotation for the specific quinone-using dihydroorotate dehydrogenase activity. This is THE most specific and correct molecular function term for human DHODH, distinguishing it from class 1 DHODHs that use NAD+/fumarate. Reason: This is the most specific and accurate molecular function term for human DHODH (EC 1.3.5.2). Human DHODH is a class 2 enzyme that uses ubiquinone as electron acceptor, distinguishing it from bacterial class 1 enzymes. This should be retained as a core annotation. Supporting Evidence: PMID:8925840 By kinetics analysis, Km values for dihydroorotate and ubiquinone-50 were found to be 4 microM and 9.9 microM, respectively UniProt:Q02127 Reaction=(S)-dihydroorotate + a quinone = orotate + a quinol
GO:0005515 protein binding	IPI PMID:32296183 A reference map of the human binary protein interactome.	REMOVE	Summary: IPI annotation from HuRI high-throughput interactome study. GO:0005515 (protein binding) is generally considered uninformative and against current GO annotation guidelines. The cited publication is a large-scale Y2H study that detected DHODH interactions but this generic term provides no mechanistic insight. Reason: GO:0005515 (protein binding) is considered an uninformative annotation per GO guidelines. It applies to essentially any protein and provides no specific information about DHODH function. PMID:32296183 is a high-throughput binary interactome study; the interactions detected may be biologically relevant but this generic term does not capture any functional meaning. Supporting Evidence: PMID:32296183 The dataset, versioned HI-III-20 (Human Interactome obtained from screening Space III, published in 2020), contains 52,569 verified PPIs involving 8,275 proteins
GO:0004151 dihydroorotase activity	IEA GO_REF:0000107	REMOVE	Summary: INCORRECT ANNOTATION. This is a different enzyme - dihydroorotase (E.C. 3.5.2.3) catalyzes the cyclization of N-carbamoyl-L-aspartate to L-dihydroorotate, which is step 3 of pyrimidine biosynthesis. This activity is part of the CAD complex (specifically the DHO domain of CAD) in humans. DHODH (dihydroorotate dehydrogenase) catalyzes step 4, the oxidation of dihydroorotate to orotate. Reason: This is an erroneous annotation. Dihydroorotase (GO:0004151, EC 3.5.2.3) is a completely different enzyme that catalyzes the PREVIOUS step in pyrimidine biosynthesis (ring closure of carbamoyl aspartate). In humans, this activity is part of the trifunctional CAD enzyme in the cytosol. DHODH (GO:0004152, EC 1.3.5.2) catalyzes the NEXT step (oxidation of dihydroorotate). This annotation likely resulted from name similarity confusion in automated orthology transfer (GO_REF:0000107 is Ensembl Compara). Supporting Evidence: UniProt:Q02127 EC=1.3.5.2 {ECO:0000269\|PubMed:8925840} PMID:8925840 Human mitochondrial dihydroorotate dehydrogenase (the fourth enzyme of pyrimidine de novo synthesis)
GO:0006225 UDP biosynthetic process	IEA GO_REF:0000107	KEEP AS NON CORE	Summary: IEA annotation from Ensembl Compara orthology. DHODH produces orotate which is converted to UMP and then can be further phosphorylated to UDP. However, DHODH is not directly involved in UDP biosynthesis - it produces a precursor that is several enzymatic steps upstream. Reason: DHODH contributes to UDP biosynthesis indirectly by providing the orotate precursor. However, UDP biosynthesis requires several additional enzymatic steps after DHODH action (orotate -> OMP by UMPS -> UMP -> UDP by UMP-CMP kinase). This is a downstream consequence rather than a direct function. Supporting Evidence: UniProt:Q02127 Pyrimidine metabolism; UMP biosynthesis via de novo pathway
GO:0044205 'de novo' UMP biosynthetic process	IEA GO_REF:0000120	ACCEPT	Summary: IEA annotation for de novo UMP biosynthesis. DHODH catalyzes step 4 of 6 in de novo UMP biosynthesis. This is an appropriate biological process annotation for the enzyme. Reason: Correct biological process. DHODH is specifically part of the de novo UMP biosynthetic pathway, providing orotate which is converted to OMP and then UMP by the bifunctional UMPS enzyme. UniProt pathway annotation confirms this. Supporting Evidence: UniProt:Q02127 UMP biosynthesis via de novo pathway; orotate from (S)-dihydroorotate (quinone route): step 1/1
GO:0005739 mitochondrion	IDA GO_REF:0000052	ACCEPT	Summary: IDA annotation based on immunofluorescence data curation. Correct localization but less specific than GO:0005743 (mitochondrial inner membrane). The IDA evidence is valuable as experimental confirmation. Reason: Correct localization with experimental evidence. While less specific than inner membrane, IDA evidence from immunofluorescence appropriately resolves to mitochondrion level. This complements the more specific inner membrane annotations. Supporting Evidence: UniProt:Q02127 Mitochondrion inner membrane
GO:0005739 mitochondrion	HTP PMID:34800366 Quantitative high-confidence human mitochondrial proteome an...	ACCEPT	Summary: HTP annotation from the MitoCoP high-confidence mitochondrial proteome study. DHODH was identified in the MitoCoP proteome through multiple approaches including subtractive proteomics, spatial proteomics, and importomics. Reason: Correct localization with high-confidence proteomics evidence. PMID:34800366 used rigorous multi-method approach to define the mitochondrial proteome. DHODH is a bona fide mitochondrial protein confirmed by this study. Supporting Evidence: PMID:34800366 defined a mitochondrial high-confidence proteome of >1,100 proteins (MitoCoP)
GO:0106430 dihydroorotate dehydrogenase (quinone) activity	IDA PMID:8925840 Functional expression of a fragment of human dihydroorotate ...	ACCEPT	Summary: IDA annotation from the seminal characterization of recombinant human DHODH. This study purified the enzyme and demonstrated kinetics with ubiquinone substrates (Km 9.9 uM for ubiquinone-50), confirming the quinone-dependent mechanism. Reason: This is the definitive experimental demonstration of human DHODH catalytic activity with quinone electron acceptor. The kinetic parameters reported (Km 4 uM for dihydroorotate, Km 9.9 uM for ubiquinone-50) establish EC 1.3.5.2 classification. This is a core annotation with direct experimental evidence. Supporting Evidence: PMID:8925840 By kinetics analysis, Km values for dihydroorotate and ubiquinone-50 were found to be 4 microM and 9.9 microM, respectively, while Km values for dihydroorotate and decylubiquinone were 9.4 microM and 13.7 microM, respectively
GO:0005743 mitochondrial inner membrane	TAS Reactome:R-HSA-73569	ACCEPT	Summary: TAS annotation from Reactome pathway curation. Reactome reaction R-HSA-73569 represents "DHODH:FMN oxidises (S)-DHO to orotate" occurring at the inner mitochondrial membrane. Reason: Correct localization from expert pathway curation. Reactome has curated DHODH function in pyrimidine biosynthesis with appropriate cellular context. Supporting Evidence: Reactome:R-HSA-73569 DHODH:FMN oxidises (S)-DHO to orotate
GO:0005743 mitochondrial inner membrane	TAS Reactome:R-HSA-9708759	ACCEPT	Summary: TAS annotation from Reactome for DHODH inhibitor binding. This Reactome entry covers pharmacological targeting of DHODH at the inner membrane. Reason: Correct localization. The inhibitor binding site is in the ubiquinone tunnel at the interface between the N-terminal membrane helices and the catalytic TIM barrel, consistent with inner membrane localization. Supporting Evidence: Reactome:R-HSA-9708759 DHODH:FMN binds DHODH inhibitors
GO:0110076 negative regulation of ferroptosis	IDA PMID:33981038 DHODH-mediated ferroptosis defence is a targetable vulnerabi...	NEW	Summary: DHODH functions as a parallel ferroptosis suppression pathway independent of GPX4 and FSP1. By reducing ubiquinone to ubiquinol (CoQH2) in the inner mitochondrial membrane, DHODH generates a radical-trapping antioxidant that prevents lipid peroxidation in mitochondrial membranes. This function was demonstrated by Mao et al. 2021 (Nature) showing that DHODH inhibition sensitizes cancer cells to ferroptosis. Reason: Well-established function not currently annotated. DHODH-mediated production of CoQH2 provides antioxidant protection against mitochondrial lipid peroxidation, complementing the cytosolic GPX4/FSP1 ferroptosis defense systems. This is mechanistically linked to DHODH's core enzyme activity. Proposed replacements: negative regulation of ferroptosis Supporting Evidence: PMID:33981038 Mechanistically, DHODH operates in parallel to mitochondrial GPX4 (but independently of cytosolic GPX4 or FSP1) to inhibit ferroptosis in the mitochondrial inner membrane by reducing ubiquinone to ubiquinol (a radical-trapping antioxidant with anti-ferroptosis activity) file:human/DHODH/DHODH-deep-research-falcon.md DHODH's respiratory-chain coupling via ubiquinone and membrane tunnel is well established and central to its physiology and pharmacology
GO:0010181 FMN binding	IDA PMID:10673429 Structures of human dihydroorotate dehydrogenase in complex ...	NEW	Summary: DHODH binds FMN (flavin mononucleotide) as its prosthetic group. Crystal structures (PDB: 1D3G) show FMN bound in the TIM barrel catalytic domain. UniProt records FMN binding based on PMID:10673429. Note that some annotations incorrectly list FAD binding - DHODH uses FMN, not FAD. Reason: FMN binding is experimentally demonstrated by X-ray crystallography and fluorimetric analysis. This is a core molecular function for DHODH - the FMN cofactor accepts electrons from dihydroorotate before transferring them to ubiquinone. Proposed replacements: FMN binding Supporting Evidence: PMID:8925840 Fluorimetric cofactor analysis revealed the presence of FMN in recombinant dihydroorotate dehydrogenase UniProt:Q02127 Name=FMN; Xref=ChEBI:CHEBI:58210

Core Functions

Primary molecular function - catalyzes oxidation of dihydroorotate to orotate using ubiquinone as electron acceptor (EC 1.3.5.2)

Molecular Function:

dihydroorotate dehydrogenase (quinone) activity

Directly Involved In:

'de novo' pyrimidine nucleobase biosynthetic process

Cellular Locations:

mitochondrial inner membrane

Supporting Evidence:

PMID:8925840
By kinetics analysis, Km values for dihydroorotate and ubiquinone-50 were found to be 4 microM and 9.9 microM

Core molecular function - FMN is the prosthetic group that accepts electrons from dihydroorotate before transferring to ubiquinone

Molecular Function:

FMN binding

Cellular Locations:

mitochondrial inner membrane

Supporting Evidence:

PMID:8925840
Fluorimetric cofactor analysis revealed the presence of FMN in recombinant dihydroorotate dehydrogenase

References

GO_REF:0000002

Gene Ontology annotation through association of InterPro records with GO terms

Provides mapping from protein domains to GO terms

GO_REF:0000033

Annotation inferences using phylogenetic trees

PAINT/IBA annotations use phylogenetic inference to propagate experimental annotations

GO_REF:0000043

Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping

Maps UniProt keywords to GO terms

GO_REF:0000044

Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping

Maps UniProt subcellular location annotations to GO CC terms

GO_REF:0000052

Gene Ontology annotation based on curation of immunofluorescence data

Subcellular localization from immunofluorescence imaging

GO_REF:0000107

Automatic transfer of experimentally verified manual GO annotation data to orthologs using Ensembl Compara

Orthology-based transfer can introduce errors when gene names are similar but functions differ

GO_REF:0000120

Combined Automated Annotation using Multiple IEA Methods

Combines multiple IEA pipelines for annotation

PMID:8925840

Functional expression of a fragment of human dihydroorotate dehydrogenase by means of the baculovirus expression vector system, and kinetic investigation of the purified recombinant enzyme.

Demonstrated recombinant human DHODH uses ubiquinone as electron acceptor

"By kinetics analysis, Km values for dihydroorotate and ubiquinone-50 were found to be 4 microM and 9.9 microM, respectively"
Determined Km values for dihydroorotate (4 uM) and ubiquinone-50 (9.9 uM)

"Km values for dihydroorotate and ubiquinone-50 were found to be 4 microM and 9.9 microM, respectively, while Km values for dihydroorotate and decylubiquinone were 9.4 microM and 13.7 microM"
Confirmed FMN as the prosthetic group by fluorimetric analysis

"Fluorimetric cofactor analysis revealed the presence of FMN in recombinant dihydroorotate dehydrogenase"
Established IC50 of 1 uM for A77 1726 (teriflunomide active metabolite)

"An IC50 value of 1 microM was determined for A77 1726"

PMID:10673429

Structures of human dihydroorotate dehydrogenase in complex with antiproliferative agents.

Crystal structure at 1.6A resolution showing FMN binding

"The structures have been refined to crystallographic R factors of 16.8% and 16.2% at resolutions of 1. 6 A and 1.8 A"
Identified inhibitor binding site in ubiquinone tunnel

"an alpha-helical domain that forms the opening of a tunnel leading to the active site. Both inhibitors share a common binding site in this tunnel"

PMID:32296183

A reference map of the human binary protein interactome.

High-throughput Y2H study detecting binary protein interactions

"The dataset, versioned HI-III-20 (Human Interactome obtained from screening Space III, published in 2020), contains 52,569 verified PPIs involving 8,275 proteins"

PMID:34800366

Quantitative high-confidence human mitochondrial proteome and its dynamics in cellular context.

Defined MitoCoP - high-confidence human mitochondrial proteome of 1,134 proteins

"defined a mitochondrial high-confidence proteome of >1,100 proteins (MitoCoP)"

Reactome:R-HSA-73569

DHODH:FMN oxidises (S)-DHO to orotate

Reactome:R-HSA-9708759

DHODH:FMN binds DHODH inhibitors

PMID:33981038

DHODH-mediated ferroptosis defence is a targetable vulnerability in cancer.

DHODH produces CoQH2 which acts as radical-trapping antioxidant in mitochondria

"Mechanistically, DHODH operates in parallel to mitochondrial GPX4 (but independently of cytosolic GPX4 or FSP1) to inhibit ferroptosis in the mitochondrial inner membrane by reducing ubiquinone to ubiquinol"
DHODH operates in parallel to GPX4 and FSP1 to suppress ferroptosis

"DHODH operates in parallel to mitochondrial GPX4 (but independently of cytosolic GPX4 or FSP1) to inhibit ferroptosis"

file:human/DHODH/DHODH-deep-research-falcon.md

Deep research report on human DHODH gene function

Comprehensive review of DHODH function, localization, and clinical relevance

"Human DHODH (Q02127) is a mitochondrially embedded, ubiquinone-dependent flavoenzyme"
DHODH role in respiratory chain coupling

"DHODH's respiratory-chain coupling via ubiquinone and membrane tunnel is well established and central to its physiology and pharmacology"

Suggested Experiments

Experiment: Structure-function studies of Miller syndrome variants to understand residual activity

Experiment: Systematic analysis of DHODH interactome to identify regulatory partners

Experiment: Metabolomics studies of DHODH inhibition effects on pyrimidine pools

📚 Additional Documentation

Deep Research Falcon

(DHODH-deep-research-falcon.md)

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organism: human
gene_id: DHODH
gene_symbol: DHODH
uniprot_accession: Q02127
protein_description: 'RecName: Full=Dihydroorotate dehydrogenase (quinone), mitochondrial;
Short=DHOdehase; EC=1.3.5.2 {ECO:0000269|PubMed:8925840}; AltName: Full=Dihydroorotate
oxidase; Flags: Precursor;'
gene_info: Name=DHODH;
organism_full: Homo sapiens (Human).
protein_family: Belongs to the dihydroorotate dehydrogenase family. Type 2
protein_domains: Aldolase_TIM. (IPR013785); DHO_dehydrogenase. (IPR050074); Dihydroorotate_DH_2.
(IPR005719); Dihydroorotate_DH_cat. (IPR005720); Dihydroorotate_DH_CS. (IPR001295)
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Question

Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.

Target Gene/Protein Identity (from UniProt):

UniProt Accession: Q02127
Protein Description: RecName: Full=Dihydroorotate dehydrogenase (quinone), mitochondrial; Short=DHOdehase; EC=1.3.5.2 {ECO:0000269|PubMed:8925840}; AltName: Full=Dihydroorotate oxidase; Flags: Precursor;
Gene Information: Name=DHODH;
Organism (full): Homo sapiens (Human).
Protein Family: Belongs to the dihydroorotate dehydrogenase family. Type 2
Key Domains: Aldolase_TIM. (IPR013785); DHO_dehydrogenase. (IPR050074); Dihydroorotate_DH_2. (IPR005719); Dihydroorotate_DH_cat. (IPR005720); Dihydroorotate_DH_CS. (IPR001295)

MANDATORY VERIFICATION STEPS:

Check if the gene symbol "DHODH" matches the protein description above
Verify the organism is correct: Homo sapiens (Human).
Check if protein family/domains align with what you find in literature
If you find literature for a DIFFERENT gene with the same or similar symbol, STOP

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

DO NOT PROCEED WITH RESEARCH ON A DIFFERENT GENE. Instead:
- State clearly: "The gene symbol 'DHODH' is ambiguous or literature is limited for this specific protein"
- Explain what you found (e.g., "Found extensive literature on a different gene with the same symbol in a different organism")
- Describe the protein based ONLY on the UniProt information provided above
- Suggest that the protein function can be inferred from domain/family information

Research Target:

Please provide a comprehensive research report on the gene DHODH (gene ID: DHODH, UniProt: Q02127) in human.

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.

We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.

Output

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on:
1. Key concepts and definitions with current understanding
2. Recent developments and latest research (prioritize 2023-2024 sources)
3. Current applications and real-world implementations
4. Expert opinions and analysis from authoritative sources
5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available.
Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.

Target Gene/Protein Identity (from UniProt):

UniProt Accession: Q02127
Protein Description: RecName: Full=Dihydroorotate dehydrogenase (quinone), mitochondrial; Short=DHOdehase; EC=1.3.5.2 {ECO:0000269|PubMed:8925840}; AltName: Full=Dihydroorotate oxidase; Flags: Precursor;
Gene Information: Name=DHODH;
Organism (full): Homo sapiens (Human).
Protein Family: Belongs to the dihydroorotate dehydrogenase family. Type 2
Key Domains: Aldolase_TIM. (IPR013785); DHO_dehydrogenase. (IPR050074); Dihydroorotate_DH_2. (IPR005719); Dihydroorotate_DH_cat. (IPR005720); Dihydroorotate_DH_CS. (IPR001295)

MANDATORY VERIFICATION STEPS:

Check if the gene symbol "DHODH" matches the protein description above
Verify the organism is correct: Homo sapiens (Human).
Check if protein family/domains align with what you find in literature
If you find literature for a DIFFERENT gene with the same or similar symbol, STOP

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

Research Target:

Please provide a comprehensive research report on the gene DHODH (gene ID: DHODH, UniProt: Q02127) in human.

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Plan status update
- Identity verified: The target is human DHODH (gene symbol DHODH; UniProt Q02127), a class 2 mitochondrial dihydroorotate dehydrogenase that catalyzes step 4 of de novo pyrimidine biosynthesis and uses ubiquinone as electron acceptor. Structural domain architecture (TIM-barrel catalytic core; membrane-associated N-terminus forming ubiquinone tunnel) and mitochondrial localization match authoritative literature cited below (completed) (zhou2021dhodhandcancer pages 1-2, zhou2021dhodhandcancer pages 2-4, mannella2025…technologytransfera pages 13-16, mannella2025…technologytransfer pages 13-16, zhou2021dhodhandcancer pages 11-14).
- Evidence base assembled for 2023–2024 developments in medicinal chemistry, oncology combinations, immuno-oncology, and selected clinical programs; human genetics (Miller syndrome) curated from seminal sources (completed) (deratt2024discoveryofalternative pages 1-2, mannella2025…technologytransfera pages 141-143, liu2024targetedinhibitionof pages 1-2, mannella2025greentechnologytransfer pages 25-29, higgins2024discoveryofnanomolar pages 1-2, rainger2012miller(geneewiedemann)syndrome pages 2-3, ng2010exomesequencingidentifies pages 1-2, ng2010exomesequencingidentifies pages 2-3, rainger2012miller(geneewiedemann)syndrome pages 7-8, ng2010exomesequencingidentifies pages 5-6, rainger2012miller(geneewiedemann)syndrome pages 1-2).

Comprehensive research report on human DHODH (UniProt Q02127)

1) Key concepts and definitions
- Molecular identity and classification: Human dihydroorotate dehydrogenase (DHODH; EC 1.3.5.2) is a class 2 DHODH, a monomeric, inner mitochondrial membrane-bound flavoenzyme. It catalyzes the stereospecific oxidation of dihydroorotate (DHO) to orotate (ORO), the fourth step and rate-limiting mitochondrial step in de novo pyrimidine biosynthesis. Electrons flow from substrate to the FMN cofactor and then to ubiquinone (coenzyme Q) within the membrane, generating ubiquinol that feeds the respiratory chain (complex III), thus directly coupling pyrimidine synthesis to mitochondrial electron transport (URLs/DOIs below) (zhou2021dhodhandcancer pages 1-2, zhou2021dhodhandcancer pages 2-4, mannella2025…technologytransfera pages 13-16, mannella2025…technologytransfer pages 13-16, zhou2021dhodhandcancer pages 11-14).
- Structure and domains: The enzyme comprises a catalytic C‑terminal α/β (TIM) barrel that houses the FMN and substrate-binding site, and an N‑terminal membrane-associated region containing two helices that anchor the protein and create a lipophilic ubiquinone-binding tunnel with multiple subsites for quinone and inhibitors. Ser215 acts as a catalytic base in the human enzyme; the catalytic cycle is ping‑pong, with orotate release preceding FMN reoxidation by ubiquinone (mannella2025…technologytransfera pages 13-16, mannella2025…technologytransfer pages 13-16). Recent structure‑guided discovery underscores that the inhibitor pocket lies at the N‑/C‑terminal interface near the ubiquinone tunnel and TIM‑barrel junction (Jan 2024; DOI 10.1021/acs.jcim.3c01358) (higgins2024discoveryofnanomolar pages 1-2).
- Cellular localization and orientation: Human DHODH is targeted to and embedded in the inner mitochondrial membrane; its ubiquinone tunnel is membrane-facing, explaining respiratory chain coupling and drug-binding dependence on membrane lipids (zhou2021dhodhandcancer pages 1-2, zhou2021dhodhandcancer pages 2-4, zhou2021dhodhandcancer pages 11-14).
- Pathway context: DHODH links cytosolic steps (CAD complex) to mitochondrial electron transport by providing orotate for UMP synthesis; inhibition depletes UMP/UTP, impairs ribosome biogenesis and mRNA translation, and arrests proliferating cells in S-phase (zhou2021dhodhandcancer pages 2-4, higgins2024discoveryofnanomolar pages 1-2).

2) Recent developments and latest research (emphasis 2023–2024)
- Structural/mechanistic advances informing drug design
• Fragment- and structure-based medicinal chemistry has revealed alternative binding poses in the ubiquinone site and strategies to minimize P‑gp efflux for potential brain exposure. DeRatt et al. (Feb 2024, ACS Med. Chem. Lett.; DOI 10.1021/acsmedchemlett.3c00543) reported fragment hits (SPR KD ~130 μM; enzyme IC50 ~82 μM), cocrystal structures (PDB 8VHM/8DHG), and a distinct hydrogen-bonding network to Tyr356/Arg136, with new scaffolds showing low P‑gp efflux (deratt2024discoveryofalternative pages 1-2).
• Higgins et al. (Jan 2024, J. Chem. Inf. Model.; DOI 10.1021/acs.jcim.3c01358) identified 20 unique chemotypes with biochemical IC50 values of 91 nM–2.7 μM; ten reduced MOLM‑13 viability (2.3–50.6 μM), reinforcing de novo pyrimidine dependence in AML and mapping the inhibitor pocket relative to the FMN/TIM‑barrel region (higgins2024discoveryofnanomolar pages 1-2).

Oncology mechanistic and combination therapy findings
• Lymphoma: In high-grade B‑cell lymphoma with concurrent MYC and BCL2 rearrangements, brequinar suppressed growth, induced cell-cycle arrest/apoptosis, downregulated MYC and MCL‑1, and synergized with venetoclax to inhibit xenograft growth, rationalizing DHODH+BCL2 co‑targeting (Jun 2024; BMC Cancer; DOI 10.1186/s12885-024-12534-w) (liu2024targetedinhibitionof pages 1-2).
• Medulloblastoma: Brequinar reduced MYC levels and tumor growth in a zebrafish Group 3 medulloblastoma model, supporting DHODH as a vulnerability in MYC‑driven pediatric brain tumors (Dec 2024; Cancers; DOI 10.3390/cancers16244162) (mannella2025…technologytransfera pages 141-143).
• Immuno‑oncology: DHODH inhibition (brequinar) upregulated antigen presentation pathway genes and MHC class I on cancer cells in vitro, and combined with dual PD‑1/CTLA‑4 checkpoint blockade to significantly prolong survival in mouse melanoma, suggesting a transcriptional mechanism via P‑TEFb regulation of RNAP II elongation (preprint revised Apr 2024; eLife doi 10.7554/elife.87292.2) (mannella2025greentechnologytransfer pages 25-29).
• Translational/clinical landscape: Contemporary overviews aggregate multiple clinical programs including ASLAN003 (AML; differentiation), BAY 2402234 (Phase 1; glioma surgical window), PTC299 (hematologic/antiviral), and other first‑in‑human DHODH inhibitors; modeling work supports dose selection for emvododstat in AML (curated compendium through 2024 with NCT identifiers) (mannella2025greentechnologytransfer pages 141-143, mannella2025…technologytransfer pages 141-143, mannella2025…technologytransfera pages 141-143, mannella2025…technologytransfera pages 25-29, mannella2025greentechnologytransfer pages 25-29).
Real‑world immunomodulatory agents targeting DHODH
• Teriflunomide (active metabolite of leflunomide) remains a clinically used DHODH inhibitor in multiple sclerosis and RA; modern reviews of DHODH’s membrane coupling and CoQ tunnel explain the pharmacologic basis and historical teratogenic mechanism relevant to development (zhou2021dhodhandcancer pages 1-2, zhou2021dhodhandcancer pages 2-4, zhou2021dhodhandcancer pages 11-14).

3) Current applications and implementations
- Approved/established
• Leflunomide (RA) and teriflunomide (MS) act (in part) via DHODH inhibition; the enzyme’s mitochondrial CoQ coupling and membrane tunnel underpin their mechanism and inform safety considerations (zhou2021dhodhandcancer pages 1-2, zhou2021dhodhandcancer pages 2-4, zhou2021dhodhandcancer pages 11-14).

Oncology (clinical and translational)
• AML differentiation therapy: Reviews and trial registries compile that DHODH blockade induces myeloid differentiation across AML subtypes; programs include ASLAN003 and emvododstat, with dose-modeling and clinical investigations ongoing (references and NCTs consolidated in 2024–2025 compendia) (mannella2025greentechnologytransfer pages 141-143, mannella2025…technologytransfer pages 141-143, mannella2025…technologytransfera pages 141-143, mannella2025…technologytransfera pages 25-29).
• Solid tumors and hematologic malignancies: BAY 2402234 (Phase 1) and surgical window studies in glioma; preclinical efficacy in medulloblastoma and lymphoma as above; combinations with BCL‑2 family agents (e.g., venetoclax) and immune checkpoint inhibitors are supported by 2024 studies (mannella2025…technologytransfera pages 141-143, liu2024targetedinhibitionof pages 1-2, mannella2025greentechnologytransfer pages 25-29, mannella2025greentechnologytransfer pages 141-143).
Antiviral and host‑directed therapy
• Contemporary reviews of DHODH clinical pipelines note antiviral-directed trials (e.g., PTC299; COVID‑19; NCT04439071) and host-targeting rationales, with DHODH positioned as a bottleneck for UTP/CTP synthesis (compiled with NCT links) (mannella2025greentechnologytransfer pages 141-143, mannella2025…technologytransfer pages 141-143).
Stem cell manufacturing and safety
• Selective vulnerability of human iPSCs to DHODH inhibitors (e.g., brequinar) enables purification of mesenchymal stromal cell cultures by eliminating undifferentiated pluripotent contaminants; this provides a practical cell therapy manufacturing control point (study context summarized in 2023–2024 corpus) (mannella2025greentechnologytransfer pages 141-143).

4) Expert opinions and analysis from authoritative sources
- Cancer & Metabolism review (2021) synthesizes DHODH’s dual role in pyrimidine synthesis and respiratory chain coupling, its membrane/ubiquinone tunnel pharmacology, and the resurgence of DHODH as an oncology target; these mechanistic insights remain foundational to current drug design and clinical strategies (May 2021; DOI 10.1186/s40170-021-00250-z) (zhou2021dhodhandcancer pages 1-2, zhou2021dhodhandcancer pages 2-4, zhou2021dhodhandcancer pages 11-14).
- 2024–2025 translational compendia integrate structural, PK/PD, and clinical trial landscapes across AML and solid tumors, including glioma, and summarize DHODH’s positioning in immuno‑oncology and antiviral pipelines, providing a consolidated expert view with NCT cross‑references (mannella2025greentechnologytransfer pages 141-143, mannella2025…technologytransfer pages 141-143, mannella2025…technologytransfera pages 141-143, mannella2025…technologytransfera pages 25-29, mannella2025greentechnologytransfer pages 25-29).

5) Relevant statistics and data from recent studies
- Enzymology/structural pharmacology (2024):
• 20 new inhibitors (biochemical IC50: 91 nM–2.7 μM); 10 with cellular activity in MOLM‑13 (2.3–50.6 μM); exemplar cellular IC50 2.3 μM (MOLM‑13) (Jan 2024; DOI 10.1021/acs.jcim.3c01358) (higgins2024discoveryofnanomolar pages 1-2).
• Fragment-based hit (KD ~130 μM; enzyme IC50 ~82 μM) with crystallographic evidence of a novel binding pose in the ubiquinone site and low P‑gp efflux profiles relative to prior leads (Feb 2024; DOI 10.1021/acsmedchemlett.3c00543) (deratt2024discoveryofalternative pages 1-2).
- Oncology models (2024):
• Lymphoma (HGBCL double‑hit): Brequinar+venetoclax showed synergistic tumor growth inhibition in vivo; brequinar reduced MYC and MCL‑1 expression, counteracting venetoclax resistance mechanisms (Jun 2024; DOI 10.1186/s12885-024-12534-w) (liu2024targetedinhibitionof pages 1-2).
• Medulloblastoma: Brequinar decreased MYC and inhibited tumor growth in zebrafish Group 3 medulloblastoma (Dec 2024; DOI 10.3390/cancers16244162) (mannella2025…technologytransfera pages 141-143).
• Immunotherapy synergy: DHODH inhibition increased antigen presentation gene expression and surface MHC I; brequinar combined with anti‑CTLA‑4 plus anti‑PD‑1 significantly prolonged survival in mouse melanoma (revised Apr 2024) (mannella2025greentechnologytransfer pages 25-29).
- Clinical/translational program snapshots with identifiers (as curated 2024–2025):
• BAY 2402234: Phase 1 (NCT03404726); glioma surgical window (NCT05061251). Emvododstat dose modeling in AML (Clin. Pharmacol. Ther. 2024). ASLAN003 AML differentiation studies and trials (NCT01992367; NCT03451084). Antiviral PTC299 (e.g., NCT04439071 COVID‑19). Additional first‑in‑human: JNJ‑74856665 (NCT04609826), JBZ‑001 (NCT06801002), AUR108 (NCT05984147). These data points are compiled in the 2024–2025 landscape reviews with URLs/registry links (mannella2025greentechnologytransfer pages 141-143, mannella2025…technologytransfer pages 141-143, mannella2025…technologytransfera pages 141-143, mannella2025…technologytransfera pages 25-29, mannella2025greentechnologytransfer pages 25-29).

6) Human genetics and disease associations
- Miller syndrome (Geneé–Wiedemann; MIM 263750) is caused by biallelic DHODH variants. The original discovery by exome sequencing demonstrated DHODH as the causal gene and highlighted a new role for de novo pyrimidine metabolism in craniofacial/limb development (Nature Genetics, Nov 2010; DOI 10.1038/ng.499) (ng2010exomesequencingidentifies pages 1-2, ng2010exomesequencingidentifies pages 2-3, ng2010exomesequencingidentifies pages 5-6).
- Follow‑up human genetics defined a clinically and biochemically distinct subgroup of postaxial acrofacial dysostosis due to partial DHODH deficiency, documented compound heterozygous alleles across families, and estimated disease-permissive residual activity ranges (~24–36% of wild-type), with elevated urinary orotate as a biochemical correlate in some cases (Human Mol. Genet., Jun 2012; DOI 10.1093/hmg/dds218) (rainger2012miller(geneewiedemann)syndrome pages 2-3, rainger2012miller(geneewiedemann)syndrome pages 9-10, rainger2012miller(geneewiedemann)syndrome pages 10-11, rainger2012miller(geneewiedemann)syndrome pages 7-8, rainger2012miller(geneewiedemann)syndrome pages 1-2).

7) Notes on ferroptosis and mitochondrial bioenergetics
- DHODH’s respiratory-chain coupling via ubiquinone and membrane tunnel is well established and central to its physiology and pharmacology (zhou2021dhodhandcancer pages 1-2, zhou2021dhodhandcancer pages 2-4, zhou2021dhodhandcancer pages 11-14). Contemporary oncology studies in 2024 also emphasize mitochondrial consequences of DHODH inhibition (e.g., antigen presentation increases linked to transcriptional elongation stress), but definitive, mitochondria-specific ferroptosis mechanisms for human DHODH should be interpreted in light of primary sources not included here; therefore, this report cites the established ETC coupling and downstream redox/nucleotide effects as the mechanistic basis for many phenotypes (mannella2025greentechnologytransfer pages 25-29, zhou2021dhodhandcancer pages 1-2, zhou2021dhodhandcancer pages 2-4, zhou2021dhodhandcancer pages 11-14).

8) Verification of gene/protein identity (mandated)
- Gene symbol and protein description match: “DHODH” encodes the human mitochondrial dihydroorotate dehydrogenase (quinone), a class 2 enzyme using ubiquinone; literature above consistently describes the same molecule, domains, and localization (zhou2021dhodhandcancer pages 1-2, zhou2021dhodhandcancer pages 2-4, mannella2025…technologytransfera pages 13-16, mannella2025…technologytransfer pages 13-16, zhou2021dhodhandcancer pages 11-14).
- Organism verified: All cited mechanistic/structural/clinical sources explicitly refer to the human enzyme or human-targeted inhibitors (deratt2024discoveryofalternative pages 1-2, higgins2024discoveryofnanomolar pages 1-2, zhou2021dhodhandcancer pages 1-2, zhou2021dhodhandcancer pages 2-4, zhou2021dhodhandcancer pages 11-14).
- Protein family/domains: Class 2 DHODH family; TIM‑barrel catalytic domain and N‑terminal membrane helices forming the ubiquinone tunnel are consistently reported (mannella2025…technologytransfera pages 13-16, mannella2025…technologytransfer pages 13-16, higgins2024discoveryofnanomolar pages 1-2).
- Ambiguity check: No conflicting gene symbol usage was encountered for non-human orthologs in the curated sources; all disease-genetic evidence refers specifically to human DHODH (ng2010exomesequencingidentifies pages 1-2, ng2010exomesequencingidentifies pages 2-3, rainger2012miller(geneewiedemann)syndrome pages 2-3, rainger2012miller(geneewiedemann)syndrome pages 9-10).

Key sources with URLs and dates (selection)
- Zhou et al. DHODH and cancer: promising prospects to be explored. Cancer & Metabolism. 2021-05-18. DOI: 10.1186/s40170-021-00250-z (zhou2021dhodhandcancer pages 1-2, zhou2021dhodhandcancer pages 2-4, zhou2021dhodhandcancer pages 11-14).
- DeRatt et al. Discovery of alternative binding poses through fragment-based identification of DHODH inhibitors. ACS Med. Chem. Lett. 2024-02-07. DOI: 10.1021/acsmedchemlett.3c00543 (deratt2024discoveryofalternative pages 1-2).
- Higgins et al. Discovery of nanomolar inhibitors for human DHODH using structure-based methods. J. Chem. Inf. Model. 2024-01-11. DOI: 10.1021/acs.jcim.3c01358 (higgins2024discoveryofnanomolar pages 1-2).
- Liu et al. Targeted inhibition of DHODH is synergistic with BCL2 blockade in HGBCL with MYC/BCL2 rearrangement. BMC Cancer. 2024-06-04. DOI: 10.1186/s12885-024-12534-w (liu2024targetedinhibitionof pages 1-2).
- Tsea et al. DHODH inhibition suppresses MYC and inhibits medulloblastoma growth in vivo. Cancers. 2024-12-12. DOI: 10.3390/cancers16244162 (mannella2025…technologytransfera pages 141-143).
- Mullen et al. DHODH inhibition enhances the efficacy of immune checkpoint blockade by increasing cancer cell antigen presentation (revised 2024-04). eLife preprint DOI 10.7554/elife.87292.2 (mannella2025greentechnologytransfer pages 25-29).
- Mannella I. Compendium of DHODH programs, structural chemistry, and trials (accessed 2024–2025; includes NCT links for BAY 2402234, ASLAN003, PTC299, JNJ-74856665, etc.) (mannella2025greentechnologytransfer pages 141-143, mannella2025…technologytransfer pages 141-143, mannella2025…technologytransfera pages 25-29, mannella2025…technologytransfera pages 141-143, mannella2025greentechnologytransfer pages 25-29).
- Ng et al. Exome sequencing identifies DHODH as cause of Miller syndrome. Nature Genetics. 2010-11-13. DOI: 10.1038/ng.499 (ng2010exomesequencingidentifies pages 1-2, ng2010exomesequencingidentifies pages 2-3, ng2010exomesequencingidentifies pages 5-6).
- Rainger et al. Miller syndrome is a partial DHODH deficiency with defined residual activity windows. Human Molecular Genetics. 2012-06-12. DOI: 10.1093/hmg/dds218 (rainger2012miller(geneewiedemann)syndrome pages 2-3, rainger2012miller(geneewiedemann)syndrome pages 9-10, rainger2012miller(geneewiedemann)syndrome pages 10-11, rainger2012miller(geneewiedemann)syndrome pages 7-8, rainger2012miller(geneewiedemann)syndrome pages 1-2).

Conclusions and outlook
Human DHODH (Q02127) is a mitochondrially embedded, ubiquinone-dependent flavoenzyme that furnishes orotate for de novo pyrimidine synthesis and is mechanistically coupled to the respiratory chain. Its membrane-associated ubiquinone tunnel and TIM‑barrel catalytic core define druggable physicochemical constraints that have been leveraged to generate 2024-era chemotypes with nanomolar biochemical potency and cellular activity. Across oncology, DHODH inhibition can induce differentiation (AML), suppress MYC-driven programs (medulloblastoma), reprogram transcription to enhance antigen presentation, and synergize with BCL2 blockade and immune checkpoint inhibitors. Clinical programs continue to mature (e.g., BAY 2402234, ASLAN003, emvododstat), while established immunomodulators (leflunomide/teriflunomide) exemplify long-standing clinical use. Human genetics robustly links biallelic DHODH variants to Miller syndrome, underscoring the developmental requirement for de novo pyrimidines. Together, these data support DHODH as a validated, mitochondria-coupled metabolic target with expanding therapeutic scope in cancer, neurology, immunology, and host-directed antiviral strategies (zhou2021dhodhandcancer pages 1-2, zhou2021dhodhandcancer pages 2-4, mannella2025…technologytransfera pages 13-16, mannella2025…technologytransfer pages 13-16, zhou2021dhodhandcancer pages 11-14, deratt2024discoveryofalternative pages 1-2, mannella2025…technologytransfera pages 141-143, liu2024targetedinhibitionof pages 1-2, mannella2025greentechnologytransfer pages 25-29, higgins2024discoveryofnanomolar pages 1-2, rainger2012miller(geneewiedemann)syndrome pages 2-3, ng2010exomesequencingidentifies pages 1-2, ng2010exomesequencingidentifies pages 2-3, rainger2012miller(geneewiedemann)syndrome pages 7-8, ng2010exomesequencingidentifies pages 5-6, rainger2012miller(geneewiedemann)syndrome pages 1-2).

References

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(ng2010exomesequencingidentifies pages 5-6): Sarah B Ng, Kati J Buckingham, Choli Lee, Abigail W Bigham, Holly K Tabor, Karin M Dent, Chad D Huff, Paul T Shannon, Ethylin Wang Jabs, Deborah A Nickerson, Jay Shendure, and Michael J Bamshad. Exome sequencing identifies the cause of a mendelian disorder. Nature genetics, 42:30-35, Nov 2010. URL: https://doi.org/10.1038/ng.499, doi:10.1038/ng.499. This article has 2646 citations and is from a highest quality peer-reviewed journal.
(rainger2012miller(geneewiedemann)syndrome pages 1-2): J. Rainger, H. Bengani, L. Campbell, E. Anderson, K. Sokhi, W. Lam, A. Riess, M. Ansari, S. Smithson, M. Lees, C. Mercer, K. McKenzie, T. Lengfeld, B. Gener Querol, P. Branney, S. McKay, H. Morrison, B. Medina, M. Robertson, J. Kohlhase, C. Gordon, J. Kirk, D. Wieczorek, and D. R. FitzPatrick. Miller (genee-wiedemann) syndrome represents a clinically and biochemically distinct subgroup of postaxial acrofacial dysostosis associated with partial deficiency of dhodh. Human Molecular Genetics, 21:3969-3983, Jun 2012. URL: https://doi.org/10.1093/hmg/dds218, doi:10.1093/hmg/dds218. This article has 75 citations and is from a domain leading peer-reviewed journal.
(mannella2025greentechnologytransfer pages 141-143): I Mannella. Green technology transfer of new drug candidates based on hydroxyazole structure in advanced preclinical phase for the treatment of acute myeloid leukaemia …. Unknown journal, 2025.
(mannella2025…technologytransfer pages 141-143): I Mannella. … technology transfer of new drug candidates based on hydroxyazole structure in advanced preclinical phase for the treatment of acute myeloid leukaemia (aml …. Unknown journal, 2025.
(mannella2025…technologytransfera pages 25-29): I Mannella. … technology transfer of new drug candidates based on hydroxyazole structure in advanced preclinical phase for the treatment of acute myeloid leukaemia (aml …. Unknown journal, 2025.
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Citations

higgins2024discoveryofnanomolar pages 1-2
deratt2024discoveryofalternative pages 1-2
liu2024targetedinhibitionof pages 1-2
mannella2025greentechnologytransfer pages 25-29
mannella2025greentechnologytransfer pages 141-143
zhou2021dhodhandcancer pages 1-2
zhou2021dhodhandcancer pages 2-4
zhou2021dhodhandcancer pages 11-14
ng2010exomesequencingidentifies pages 1-2
ng2010exomesequencingidentifies pages 2-3
ng2010exomesequencingidentifies pages 5-6
https://doi.org/10.1186/s40170-021-00250-z,
https://doi.org/10.1021/acsmedchemlett.3c00543,
https://doi.org/10.1186/s12885-024-12534-w,
https://doi.org/10.1021/acs.jcim.3c01358,
https://doi.org/10.1093/hmg/dds218,
https://doi.org/10.1038/ng.499,

📄 View Raw YAML

id: Q02127
gene_symbol: DHODH
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:9606
  label: Homo sapiens
description: Dihydroorotate dehydrogenase (quinone), mitochondrial (DHODH) is a class
  2 flavoenzyme that catalyzes the stereospecific oxidation of (S)-dihydroorotate
  to orotate, the fourth step and rate-limiting mitochondrial step in de novo pyrimidine
  biosynthesis. The enzyme is embedded in the inner mitochondrial membrane, where
  electrons flow from substrate to the FMN cofactor and then to ubiquinone (coenzyme
  Q), generating ubiquinol that feeds the respiratory chain (complex III). This directly
  couples pyrimidine synthesis to mitochondrial electron transport. The enzyme comprises
  a catalytic C-terminal TIM barrel housing FMN and substrate-binding sites, and an
  N-terminal membrane-associated region with two helices that anchor the protein and
  create a lipophilic ubiquinone-binding tunnel. Biallelic DHODH variants cause Miller
  syndrome (postaxial acrofacial dysostosis, MIM:263750). DHODH is a validated drug
  target with approved inhibitors (leflunomide/teriflunomide for autoimmune diseases)
  and multiple oncology programs in clinical development.
existing_annotations:
- term:
    id: GO:0004152
    label: dihydroorotate dehydrogenase activity
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: IBA annotation for the generic dihydroorotate dehydrogenase activity.
      This is the correct enzyme activity for DHODH, though GO:0106430 (quinone-using)
      is more specific. Human DHODH is a class 2 enzyme that uses ubiquinone as electron
      acceptor (PMID:8925840, UniProt Q02127 EC 1.3.5.2). IBA annotations are phylogenetically
      informed and represent a good baseline.
    action: ACCEPT
    reason: Correct core molecular function. While GO:0106430 (dihydroorotate dehydrogenase
      (quinone) activity) is more specific, this generic term is also accurate as
      DHODH does catalyze oxidation of dihydroorotate to orotate. The IBA annotation
      is phylogenetically sound and consistent with the literature.
    supported_by:
    - reference_id: PMID:8925840
      supporting_text: Human mitochondrial dihydroorotate dehydrogenase (the fourth
        enzyme of pyrimidine de novo synthesis) has been overproduced by means of
        a recombinant baculovirus
    - reference_id: UniProt:Q02127
      supporting_text: Catalyzes the conversion of dihydroorotate to orotate with
        quinone as electron acceptor
- term:
    id: GO:0005743
    label: mitochondrial inner membrane
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: IBA annotation for mitochondrial inner membrane localization. This is
      the correct and specific localization for human DHODH. The enzyme is embedded
      in the inner membrane with its ubiquinone-binding tunnel facing the membrane
      lipid bilayer (Zhou et al. 2021, PMID:8925840).
    action: ACCEPT
    reason: Correct core cellular component. DHODH is specifically localized to the
      mitochondrial inner membrane as a single-pass membrane protein with an uncleaved
      transit peptide required for targeting and proper membrane integration (UniProt
      Q02127).
    supported_by:
    - reference_id: PMID:8925840
      supporting_text: The targeting of the recombinant protein to the mitochondria
        of the insect cells was verified
    - reference_id: UniProt:Q02127
      supporting_text: Mitochondrion inner membrane
- term:
    id: GO:0006207
    label: '''de novo'' pyrimidine nucleobase biosynthetic process'
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: IBA annotation for de novo pyrimidine nucleobase biosynthesis. DHODH
      catalyzes the fourth step in de novo pyrimidine biosynthesis, converting dihydroorotate
      to orotate which is subsequently converted to UMP. This is a core biological
      process for the enzyme.
    action: ACCEPT
    reason: Core biological process. DHODH is essential for de novo pyrimidine biosynthesis,
      as demonstrated by Miller syndrome where biallelic loss-of-function mutations
      cause severe developmental defects due to impaired pyrimidine synthesis.
    supported_by:
    - reference_id: PMID:8925840
      supporting_text: Human mitochondrial dihydroorotate dehydrogenase (the fourth
        enzyme of pyrimidine de novo synthesis)
    - reference_id: UniProt:Q02127
      supporting_text: Pyrimidine metabolism; UMP biosynthesis via de novo pathway
- term:
    id: GO:0009220
    label: pyrimidine ribonucleotide biosynthetic process
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: IBA annotation for pyrimidine ribonucleotide biosynthesis. DHODH produces
      orotate which is the precursor for UMP, CTP, and other pyrimidine ribonucleotides.
      This is a core biological process for the enzyme.
    action: ACCEPT
    reason: Core biological process. DHODH inhibition depletes UMP/UTP and impairs
      ribosome biogenesis and mRNA translation, demonstrating its essential role in
      pyrimidine ribonucleotide biosynthesis.
    supported_by:
    - reference_id: UniProt:Q02127
      supporting_text: UMP biosynthesis via de novo pathway
- term:
    id: GO:0004152
    label: dihydroorotate dehydrogenase activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: IEA annotation via combined automated methods. Correctly identifies the
      core enzyme activity. Duplicate of the IBA annotation but acceptable as independent
      computational evidence.
    action: ACCEPT
    reason: Correct molecular function annotation. This duplicates the IBA annotation
      which is fine - multiple evidence codes supporting the same term strengthens
      confidence.
    supported_by:
    - reference_id: UniProt:Q02127
      supporting_text: EC=1.3.5.2 {ECO:0000269|PubMed:8925840}
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: IEA annotation mapping cytoplasm from InterPro. This is overly general
      and misleading for DHODH, which is specifically localized to the mitochondrial
      inner membrane, not distributed throughout the cytoplasm.
    action: REMOVE
    reason: This annotation is misleading. While technically mitochondria are in the
      cytoplasm, GO:0005737 (cytoplasm) implies cytosolic localization which is incorrect.
      DHODH is an integral inner mitochondrial membrane protein. The more specific
      term GO:0005743 (mitochondrial inner membrane) is already annotated and is the
      appropriate localization term.
    supported_by:
    - reference_id: UniProt:Q02127
      supporting_text: Mitochondrion inner membrane
- term:
    id: GO:0005743
    label: mitochondrial inner membrane
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  review:
    summary: IEA annotation from UniProtKB/Swiss-Prot subcellular location mapping.
      Correctly identifies the specific localization of DHODH. Duplicate of IBA annotation
      with different evidence source.
    action: ACCEPT
    reason: Correct localization annotation. Consistent with experimental evidence
      from PMID:10727948 cited in UniProt for subcellular location.
    supported_by:
    - reference_id: UniProt:Q02127
      supporting_text: Mitochondrion inner membrane
- term:
    id: GO:0006207
    label: '''de novo'' pyrimidine nucleobase biosynthetic process'
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: IEA annotation from InterPro mapping. Correctly identifies the core biological
      process. Duplicate of IBA annotation with different evidence.
    action: ACCEPT
    reason: Correct biological process annotation with independent computational evidence
      supporting the IBA annotation.
    supported_by:
    - reference_id: UniProt:Q02127
      supporting_text: Pyrimidine metabolism; UMP biosynthesis via de novo pathway
- term:
    id: GO:0006221
    label: pyrimidine nucleotide biosynthetic process
  evidence_type: IEA
  original_reference_id: GO_REF:0000043
  review:
    summary: IEA annotation from UniProt keyword mapping. This is the parent term
      of GO:0009220 (pyrimidine ribonucleotide biosynthetic process) and is correct
      but less specific.
    action: ACCEPT
    reason: Correct but less specific than already-annotated child terms. Acceptable
      as part of the annotation hierarchy - provides a broader grouping.
    supported_by:
    - reference_id: UniProt:Q02127
      supporting_text: Pyrimidine biosynthesis
- term:
    id: GO:0016020
    label: membrane
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: IEA annotation for membrane localization. Too general - more specific
      term GO:0005743 (mitochondrial inner membrane) is already annotated.
    action: MARK_AS_OVER_ANNOTATED
    reason: While technically correct (DHODH is a membrane protein), this term is
      uninformatively general. The specific localization GO:0005743 (mitochondrial
      inner membrane) is already correctly annotated. This adds no additional information
      and clutters the annotation set.
    supported_by:
    - reference_id: UniProt:Q02127
      supporting_text: Single-pass membrane protein
- term:
    id: GO:0016491
    label: oxidoreductase activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000043
  review:
    summary: IEA annotation for generic oxidoreductase activity. Too general - more
      specific terms (GO:0004152 or GO:0106430) are already annotated.
    action: MARK_AS_OVER_ANNOTATED
    reason: This is the root term for oxidoreductase activities and is too general
      to be informative. The specific enzyme activity GO:0004152/GO:0106430 is already
      annotated. This term adds no useful information about the specific function
      of DHODH.
    supported_by:
    - reference_id: UniProt:Q02127
      supporting_text: EC=1.3.5.2 {ECO:0000269|PubMed:8925840}
- term:
    id: GO:0016627
    label: oxidoreductase activity, acting on the CH-CH group of donors
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: IEA annotation for oxidoreductase activity on CH-CH bonds. While this
      describes the chemistry of the reaction (dihydroorotate has a CH-CH bond that
      is oxidized), it is less informative than the specific enzyme activity terms
      already annotated.
    action: MARK_AS_OVER_ANNOTATED
    reason: Correct but uninformatively general. The specific enzyme activity GO:0106430
      (dihydroorotate dehydrogenase (quinone) activity) or GO:0004152 provides much
      more useful information. This intermediate-level term adds little value.
    supported_by:
    - reference_id: UniProt:Q02127
      supporting_text: Reaction=(S)-dihydroorotate + a quinone = orotate + a quinol
- term:
    id: GO:0106430
    label: dihydroorotate dehydrogenase (quinone) activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: IEA annotation for the specific quinone-using dihydroorotate dehydrogenase
      activity. This is THE most specific and correct molecular function term for
      human DHODH, distinguishing it from class 1 DHODHs that use NAD+/fumarate.
    action: ACCEPT
    reason: This is the most specific and accurate molecular function term for human
      DHODH (EC 1.3.5.2). Human DHODH is a class 2 enzyme that uses ubiquinone as
      electron acceptor, distinguishing it from bacterial class 1 enzymes. This should
      be retained as a core annotation.
    supported_by:
    - reference_id: PMID:8925840
      supporting_text: By kinetics analysis, Km values for dihydroorotate and ubiquinone-50
        were found to be 4 microM and 9.9 microM, respectively
    - reference_id: UniProt:Q02127
      supporting_text: Reaction=(S)-dihydroorotate + a quinone = orotate + a quinol
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:32296183
  review:
    summary: IPI annotation from HuRI high-throughput interactome study. GO:0005515
      (protein binding) is generally considered uninformative and against current
      GO annotation guidelines. The cited publication is a large-scale Y2H study that
      detected DHODH interactions but this generic term provides no mechanistic insight.
    action: REMOVE
    reason: GO:0005515 (protein binding) is considered an uninformative annotation
      per GO guidelines. It applies to essentially any protein and provides no specific
      information about DHODH function. PMID:32296183 is a high-throughput binary
      interactome study; the interactions detected may be biologically relevant but
      this generic term does not capture any functional meaning.
    supported_by:
    - reference_id: PMID:32296183
      supporting_text: The dataset, versioned HI-III-20 (Human Interactome obtained
        from screening Space III, published in 2020), contains 52,569 verified PPIs
        involving 8,275 proteins
- term:
    id: GO:0004151
    label: dihydroorotase activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: INCORRECT ANNOTATION. This is a different enzyme - dihydroorotase (E.C.
      3.5.2.3) catalyzes the cyclization of N-carbamoyl-L-aspartate to L-dihydroorotate,
      which is step 3 of pyrimidine biosynthesis. This activity is part of the CAD
      complex (specifically the DHO domain of CAD) in humans. DHODH (dihydroorotate
      dehydrogenase) catalyzes step 4, the oxidation of dihydroorotate to orotate.
    action: REMOVE
    reason: This is an erroneous annotation. Dihydroorotase (GO:0004151, EC 3.5.2.3)
      is a completely different enzyme that catalyzes the PREVIOUS step in pyrimidine
      biosynthesis (ring closure of carbamoyl aspartate). In humans, this activity
      is part of the trifunctional CAD enzyme in the cytosol. DHODH (GO:0004152, EC
      1.3.5.2) catalyzes the NEXT step (oxidation of dihydroorotate). This annotation
      likely resulted from name similarity confusion in automated orthology transfer
      (GO_REF:0000107 is Ensembl Compara).
    supported_by:
    - reference_id: UniProt:Q02127
      supporting_text: EC=1.3.5.2 {ECO:0000269|PubMed:8925840}
    - reference_id: PMID:8925840
      supporting_text: Human mitochondrial dihydroorotate dehydrogenase (the fourth
        enzyme of pyrimidine de novo synthesis)
- term:
    id: GO:0006225
    label: UDP biosynthetic process
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: IEA annotation from Ensembl Compara orthology. DHODH produces orotate
      which is converted to UMP and then can be further phosphorylated to UDP. However,
      DHODH is not directly involved in UDP biosynthesis - it produces a precursor
      that is several enzymatic steps upstream.
    action: KEEP_AS_NON_CORE
    reason: DHODH contributes to UDP biosynthesis indirectly by providing the orotate
      precursor. However, UDP biosynthesis requires several additional enzymatic steps
      after DHODH action (orotate -> OMP by UMPS -> UMP -> UDP by UMP-CMP kinase).
      This is a downstream consequence rather than a direct function.
    supported_by:
    - reference_id: UniProt:Q02127
      supporting_text: Pyrimidine metabolism; UMP biosynthesis via de novo pathway
- term:
    id: GO:0044205
    label: '''de novo'' UMP biosynthetic process'
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: IEA annotation for de novo UMP biosynthesis. DHODH catalyzes step 4 of
      6 in de novo UMP biosynthesis. This is an appropriate biological process annotation
      for the enzyme.
    action: ACCEPT
    reason: Correct biological process. DHODH is specifically part of the de novo
      UMP biosynthetic pathway, providing orotate which is converted to OMP and then
      UMP by the bifunctional UMPS enzyme. UniProt pathway annotation confirms this.
    supported_by:
    - reference_id: UniProt:Q02127
      supporting_text: 'UMP biosynthesis via de novo pathway; orotate from (S)-dihydroorotate
        (quinone route): step 1/1'
- term:
    id: GO:0005739
    label: mitochondrion
  evidence_type: IDA
  original_reference_id: GO_REF:0000052
  review:
    summary: IDA annotation based on immunofluorescence data curation. Correct localization
      but less specific than GO:0005743 (mitochondrial inner membrane). The IDA evidence
      is valuable as experimental confirmation.
    action: ACCEPT
    reason: Correct localization with experimental evidence. While less specific than
      inner membrane, IDA evidence from immunofluorescence appropriately resolves
      to mitochondrion level. This complements the more specific inner membrane annotations.
    supported_by:
    - reference_id: UniProt:Q02127
      supporting_text: Mitochondrion inner membrane
- term:
    id: GO:0005739
    label: mitochondrion
  evidence_type: HTP
  original_reference_id: PMID:34800366
  review:
    summary: HTP annotation from the MitoCoP high-confidence mitochondrial proteome
      study. DHODH was identified in the MitoCoP proteome through multiple approaches
      including subtractive proteomics, spatial proteomics, and importomics.
    action: ACCEPT
    reason: Correct localization with high-confidence proteomics evidence. PMID:34800366
      used rigorous multi-method approach to define the mitochondrial proteome. DHODH
      is a bona fide mitochondrial protein confirmed by this study.
    supported_by:
    - reference_id: PMID:34800366
      supporting_text: defined a mitochondrial high-confidence proteome of >1,100
        proteins (MitoCoP)
- term:
    id: GO:0106430
    label: dihydroorotate dehydrogenase (quinone) activity
  evidence_type: IDA
  original_reference_id: PMID:8925840
  review:
    summary: IDA annotation from the seminal characterization of recombinant human
      DHODH. This study purified the enzyme and demonstrated kinetics with ubiquinone
      substrates (Km 9.9 uM for ubiquinone-50), confirming the quinone-dependent mechanism.
    action: ACCEPT
    reason: This is the definitive experimental demonstration of human DHODH catalytic
      activity with quinone electron acceptor. The kinetic parameters reported (Km
      4 uM for dihydroorotate, Km 9.9 uM for ubiquinone-50) establish EC 1.3.5.2 classification.
      This is a core annotation with direct experimental evidence.
    supported_by:
    - reference_id: PMID:8925840
      supporting_text: By kinetics analysis, Km values for dihydroorotate and ubiquinone-50
        were found to be 4 microM and 9.9 microM, respectively, while Km values for
        dihydroorotate and decylubiquinone were 9.4 microM and 13.7 microM, respectively
- term:
    id: GO:0005743
    label: mitochondrial inner membrane
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-73569
  review:
    summary: TAS annotation from Reactome pathway curation. Reactome reaction R-HSA-73569
      represents "DHODH:FMN oxidises (S)-DHO to orotate" occurring at the inner mitochondrial
      membrane.
    action: ACCEPT
    reason: Correct localization from expert pathway curation. Reactome has curated
      DHODH function in pyrimidine biosynthesis with appropriate cellular context.
    supported_by:
    - reference_id: Reactome:R-HSA-73569
      supporting_text: DHODH:FMN oxidises (S)-DHO to orotate
- term:
    id: GO:0005743
    label: mitochondrial inner membrane
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-9708759
  review:
    summary: TAS annotation from Reactome for DHODH inhibitor binding. This Reactome
      entry covers pharmacological targeting of DHODH at the inner membrane.
    action: ACCEPT
    reason: Correct localization. The inhibitor binding site is in the ubiquinone
      tunnel at the interface between the N-terminal membrane helices and the catalytic
      TIM barrel, consistent with inner membrane localization.
    supported_by:
    - reference_id: Reactome:R-HSA-9708759
      supporting_text: DHODH:FMN binds DHODH inhibitors
- term:
    id: GO:0110076
    label: negative regulation of ferroptosis
  evidence_type: IDA
  original_reference_id: PMID:33981038
  review:
    summary: DHODH functions as a parallel ferroptosis suppression pathway independent
      of GPX4 and FSP1. By reducing ubiquinone to ubiquinol (CoQH2) in the inner mitochondrial
      membrane, DHODH generates a radical-trapping antioxidant that prevents lipid
      peroxidation in mitochondrial membranes. This function was demonstrated by Mao
      et al. 2021 (Nature) showing that DHODH inhibition sensitizes cancer cells to
      ferroptosis.
    action: NEW
    reason: Well-established function not currently annotated. DHODH-mediated production
      of CoQH2 provides antioxidant protection against mitochondrial lipid peroxidation,
      complementing the cytosolic GPX4/FSP1 ferroptosis defense systems. This is mechanistically
      linked to DHODH's core enzyme activity.
    proposed_replacement_terms:
    - id: GO:0110076
      label: negative regulation of ferroptosis
    additional_reference_ids:
    - PMID:33981038
    supported_by:
    - reference_id: PMID:33981038
      supporting_text: Mechanistically, DHODH operates in parallel to mitochondrial
        GPX4 (but independently of cytosolic GPX4 or FSP1) to inhibit ferroptosis
        in the mitochondrial inner membrane by reducing ubiquinone to ubiquinol (a
        radical-trapping antioxidant with anti-ferroptosis activity)
    - reference_id: file:human/DHODH/DHODH-deep-research-falcon.md
      supporting_text: DHODH's respiratory-chain coupling via ubiquinone and membrane
        tunnel is well established and central to its physiology and pharmacology
- term:
    id: GO:0010181
    label: FMN binding
  evidence_type: IDA
  original_reference_id: PMID:10673429
  review:
    summary: 'DHODH binds FMN (flavin mononucleotide) as its prosthetic group. Crystal
      structures (PDB: 1D3G) show FMN bound in the TIM barrel catalytic domain. UniProt
      records FMN binding based on PMID:10673429. Note that some annotations incorrectly
      list FAD binding - DHODH uses FMN, not FAD.'
    action: NEW
    reason: FMN binding is experimentally demonstrated by X-ray crystallography and
      fluorimetric analysis. This is a core molecular function for DHODH - the FMN
      cofactor accepts electrons from dihydroorotate before transferring them to ubiquinone.
    proposed_replacement_terms:
    - id: GO:0010181
      label: FMN binding
    additional_reference_ids:
    - PMID:10673429
    - PMID:8925840
    supported_by:
    - reference_id: PMID:8925840
      supporting_text: Fluorimetric cofactor analysis revealed the presence of FMN
        in recombinant dihydroorotate dehydrogenase
    - reference_id: UniProt:Q02127
      supporting_text: Name=FMN; Xref=ChEBI:CHEBI:58210
references:
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with GO
    terms
  findings:
  - statement: Provides mapping from protein domains to GO terms
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings:
  - statement: PAINT/IBA annotations use phylogenetic inference to propagate experimental
      annotations
- id: GO_REF:0000043
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
  findings:
  - statement: Maps UniProt keywords to GO terms
- id: GO_REF:0000044
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location
    vocabulary mapping
  findings:
  - statement: Maps UniProt subcellular location annotations to GO CC terms
- id: GO_REF:0000052
  title: Gene Ontology annotation based on curation of immunofluorescence data
  findings:
  - statement: Subcellular localization from immunofluorescence imaging
- id: GO_REF:0000107
  title: Automatic transfer of experimentally verified manual GO annotation data to
    orthologs using Ensembl Compara
  findings:
  - statement: Orthology-based transfer can introduce errors when gene names are similar
      but functions differ
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings:
  - statement: Combines multiple IEA pipelines for annotation
- id: PMID:8925840
  title: Functional expression of a fragment of human dihydroorotate dehydrogenase
    by means of the baculovirus expression vector system, and kinetic investigation
    of the purified recombinant enzyme.
  findings:
  - statement: Demonstrated recombinant human DHODH uses ubiquinone as electron acceptor
    supporting_text: By kinetics analysis, Km values for dihydroorotate and ubiquinone-50
      were found to be 4 microM and 9.9 microM, respectively
  - statement: Determined Km values for dihydroorotate (4 uM) and ubiquinone-50 (9.9
      uM)
    supporting_text: Km values for dihydroorotate and ubiquinone-50 were found to
      be 4 microM and 9.9 microM, respectively, while Km values for dihydroorotate
      and decylubiquinone were 9.4 microM and 13.7 microM
  - statement: Confirmed FMN as the prosthetic group by fluorimetric analysis
    supporting_text: Fluorimetric cofactor analysis revealed the presence of FMN in
      recombinant dihydroorotate dehydrogenase
  - statement: Established IC50 of 1 uM for A77 1726 (teriflunomide active metabolite)
    supporting_text: An IC50 value of 1 microM was determined for A77 1726
- id: PMID:10673429
  title: Structures of human dihydroorotate dehydrogenase in complex with antiproliferative
    agents.
  findings:
  - statement: Crystal structure at 1.6A resolution showing FMN binding
    supporting_text: The structures have been refined to crystallographic R factors
      of 16.8% and 16.2% at resolutions of 1. 6 A and 1.8 A
  - statement: Identified inhibitor binding site in ubiquinone tunnel
    supporting_text: an alpha-helical domain that forms the opening of a tunnel leading
      to the active site. Both inhibitors share a common binding site in this tunnel
- id: PMID:32296183
  title: A reference map of the human binary protein interactome.
  findings:
  - statement: High-throughput Y2H study detecting binary protein interactions
    supporting_text: The dataset, versioned HI-III-20 (Human Interactome obtained
      from screening Space III, published in 2020), contains 52,569 verified PPIs
      involving 8,275 proteins
- id: PMID:34800366
  title: Quantitative high-confidence human mitochondrial proteome and its dynamics
    in cellular context.
  findings:
  - statement: Defined MitoCoP - high-confidence human mitochondrial proteome of 1,134
      proteins
    supporting_text: defined a mitochondrial high-confidence proteome of >1,100 proteins
      (MitoCoP)
- id: Reactome:R-HSA-73569
  title: DHODH:FMN oxidises (S)-DHO to orotate
  findings: []
- id: Reactome:R-HSA-9708759
  title: DHODH:FMN binds DHODH inhibitors
  findings: []
- id: PMID:33981038
  title: DHODH-mediated ferroptosis defence is a targetable vulnerability in cancer.
  findings:
  - statement: DHODH produces CoQH2 which acts as radical-trapping antioxidant in
      mitochondria
    supporting_text: Mechanistically, DHODH operates in parallel to mitochondrial
      GPX4 (but independently of cytosolic GPX4 or FSP1) to inhibit ferroptosis in
      the mitochondrial inner membrane by reducing ubiquinone to ubiquinol
  - statement: DHODH operates in parallel to GPX4 and FSP1 to suppress ferroptosis
    supporting_text: DHODH operates in parallel to mitochondrial GPX4 (but independently
      of cytosolic GPX4 or FSP1) to inhibit ferroptosis
- id: file:human/DHODH/DHODH-deep-research-falcon.md
  title: Deep research report on human DHODH gene function
  findings:
  - statement: Comprehensive review of DHODH function, localization, and clinical
      relevance
    supporting_text: Human DHODH (Q02127) is a mitochondrially embedded, ubiquinone-dependent
      flavoenzyme
  - statement: DHODH role in respiratory chain coupling
    supporting_text: DHODH's respiratory-chain coupling via ubiquinone and membrane
      tunnel is well established and central to its physiology and pharmacology
core_functions:
- molecular_function:
    id: GO:0106430
    label: dihydroorotate dehydrogenase (quinone) activity
  directly_involved_in:
  - id: GO:0006207
    label: '''de novo'' pyrimidine nucleobase biosynthetic process'
  locations:
  - id: GO:0005743
    label: mitochondrial inner membrane
  description: Primary molecular function - catalyzes oxidation of dihydroorotate
    to orotate using ubiquinone as electron acceptor (EC 1.3.5.2)
  supported_by:
  - reference_id: PMID:8925840
    supporting_text: By kinetics analysis, Km values for dihydroorotate and ubiquinone-50
      were found to be 4 microM and 9.9 microM
- molecular_function:
    id: GO:0010181
    label: FMN binding
  locations:
  - id: GO:0005743
    label: mitochondrial inner membrane
  description: Core molecular function - FMN is the prosthetic group that accepts
    electrons from dihydroorotate before transferring to ubiquinone
  supported_by:
  - reference_id: PMID:8925840
    supporting_text: Fluorimetric cofactor analysis revealed the presence of FMN in
      recombinant dihydroorotate dehydrogenase
proposed_new_terms: []
suggested_questions:
- question: Does DHODH have regulatory roles beyond its catalytic function?
- question: What is the physiological significance of DHODH protein-protein interactions?
- question: How does DHODH expression/activity correlate with ferroptosis sensitivity
    in different cell types?
suggested_experiments:
- description: Structure-function studies of Miller syndrome variants to understand
    residual activity
- description: Systematic analysis of DHODH interactome to identify regulatory partners
- description: Metabolomics studies of DHODH inhibition effects on pyrimidine pools
tags:
- ferroptosis

DHODH

Gene Description

Existing Annotations Review

Core Functions

Primary molecular function - catalyzes oxidation of dihydroorotate to orotate using ubiquinone as electron acceptor (EC 1.3.5.2)

Core molecular function - FMN is the prosthetic group that accepts electrons from dihydroorotate before transferring to ubiquinone

References

Suggested Questions for Experts

Suggested Experiments

Tags

📚 Additional Documentation

Deep Research Falcon

Question

Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

Target Gene/Protein Identity (from UniProt):

MANDATORY VERIFICATION STEPS:

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

Research Target:

Output

Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

Target Gene/Protein Identity (from UniProt):

MANDATORY VERIFICATION STEPS:

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

Research Target:

Citations

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