id: P49748
gene_symbol: ACADVL
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:9606
  label: Homo sapiens
description: >-
  ACADVL encodes very-long-chain specific acyl-CoA dehydrogenase (VLCAD), a FAD-dependent
  flavoenzyme of the acyl-CoA dehydrogenase (ACAD) family that catalyzes the first and
  committed step of each cycle of mitochondrial fatty acid beta-oxidation. VLCAD performs
  the stereospecific alpha,beta-dehydrogenation of saturated and unsaturated acyl-CoA
  thioesters with primary chains of roughly 12 to 24 carbons (with optimal activity in the
  very-long-chain/long-chain range, e.g. palmitoyl-CoA, C16), producing the corresponding
  trans-2-enoyl-CoA and transferring electrons to the electron-transfer flavoprotein (ETF).
  Unlike the soluble matrix dehydrogenases MCAD, SCAD and LCAD, VLCAD is a homodimer of
  ~70 kDa subunits that is bound as a peripheral protein to the matrix face of the
  mitochondrial inner membrane; membrane association is required for assembly of the mature
  dimer. VLCAD is most highly expressed in heart and skeletal muscle, the tissues that depend
  on long-chain fat as a primary fuel. Loss of VLCAD activity causes very-long-chain acyl-CoA
  dehydrogenase deficiency, an inborn error of fatty acid oxidation presenting as hypertrophic
  cardiomyopathy and sudden death, hypoketotic hypoglycemia with hepatic involvement, or an
  adult-onset myopathy with exercise-induced rhabdomyolysis.
alternative_products:
- name: '1'
  id: P49748-1
- name: 2 (DeltaEx3 VLCAD {ECO:0000303|PubMed:17374501})
  id: P49748-2
  sequence_note: VSP_007734
- name: '3'
  id: P49748-3
  sequence_note: VSP_046031
existing_annotations:
# --- Annotation 1: VLCAD activity (IBA) ---
- term:
    id: GO:0017099
    label: very-long-chain fatty acyl-CoA dehydrogenase activity
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: enables
  review:
    summary: >-
      Phylogenetically inferred very-long-chain acyl-CoA dehydrogenase activity. This is the
      defining catalytic activity of VLCAD (EC 1.3.8.9) and is directly demonstrated for the
      human protein, so the IBA annotation is appropriate and captures the core molecular function.
    action: ACCEPT
    reason: >-
      VLCAD acts specifically on fatty acyl-CoAs with 12-24 carbon chains, with the very-long-chain
      activity directly demonstrated (PMID:9461620, EC 1.3.8.9 assigned via PMID:21237683). The
      phylogenetic inference at this specific level is well supported.
    supported_by:
    - reference_id: PMID:9461620
      supporting_text: "Very long-chain acyl-CoA dehydrogenase (VLCAD) is one of four flavoproteins which catalyze the initial step of the mitochondrial beta-oxidation spiral"
# --- Annotation 2: fatty-acyl-CoA binding (IBA) ---
- term:
    id: GO:0000062
    label: fatty-acyl-CoA binding
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: enables
  review:
    summary: >-
      Phylogenetically inferred binding of the acyl-CoA substrate. VLCAD necessarily binds
      fatty-acyl-CoA substrates to perform dehydrogenation; the formation of a charge-transfer
      complex between VLCAD and palmitoyl-CoA has been observed (PMID:9461620). This is a correct
      but ancillary (substrate-binding) annotation.
    action: KEEP_AS_NON_CORE
    reason: >-
      Substrate binding is a prerequisite of the catalytic activity rather than a separate core
      function; the catalytic dehydrogenase terms better represent VLCAD's role. The binding itself
      is supported by the observed VLCAD-palmitoyl-CoA charge-transfer complex (PMID:9461620).
    supported_by:
    - reference_id: PMID:9461620
      supporting_text: "preventing the formation of a charge transfer complex between VLCAD and palmitoyl-CoA"
# --- Annotation 3: acyl-CoA dehydrogenase activity (IEA, InterPro) ---
- term:
    id: GO:0003995
    label: acyl-CoA dehydrogenase activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  qualifier: enables
  review:
    summary: >-
      InterPro-based electronic annotation to the general acyl-CoA dehydrogenase activity term.
      VLCAD contains the ACAD active-site signature and is a bona fide member of the family. The
      term is correct but broader than the specific VLCAD/LCAD activity terms that are also annotated.
    action: KEEP_AS_NON_CORE
    reason: >-
      Correct general parent term subsumed by the specific GO:0017099 (very-long-chain) and
      GO:0004466 (long-chain) activities. Retained as a supporting non-core annotation.
    supported_by:
    - reference_id: PMID:9461620
      supporting_text: "Very long-chain acyl-CoA dehydrogenase (VLCAD) is one of four flavoproteins which catalyze the initial step of the mitochondrial beta-oxidation spiral"
# --- Annotation 4: long-chain acyl-CoA dehydrogenase activity (IEA, ARBA/Rhea) ---
- term:
    id: GO:0004466
    label: long-chain fatty acyl-CoA dehydrogenase activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: enables
  review:
    summary: >-
      Electronic annotation from ARBA/Rhea mapping based on EC 1.3.8.8. VLCAD has well-documented
      long-chain acyl-CoA dehydrogenase activity (classically assayed with palmitoyl-CoA, C16) in
      addition to its very-long-chain activity, so this is a valid and biologically accurate term.
    action: ACCEPT
    reason: >-
      VLCAD catalyzes dehydrogenation of long-chain acyl-CoA substrates (EC 1.3.8.8), demonstrated
      directly for the human enzyme (PMID:7668252 measures palmitic-acid beta-oxidation flux driven
      by VLCAD activity). Consistent with the IDA and TAS annotations to this same term.
    supported_by:
    - reference_id: PMID:7668252
      supporting_text: "raising VLCAD activity to approximately 20% of normal control fibroblast activity raised palmitic acid beta-oxidation flux to the level found in control fibroblasts"
# --- Annotation 5: mitochondrial inner membrane (IEA, SubCell) ---
- term:
    id: GO:0005743
    label: mitochondrial inner membrane
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  qualifier: located_in
  review:
    summary: >-
      Electronic annotation from UniProt subcellular-location mapping. VLCAD is experimentally
      localized as a peripheral protein of the mitochondrial inner membrane, distinguishing it
      from the soluble matrix ACADs. This is the core cellular localization.
    action: ACCEPT
    reason: >-
      Inner-membrane association of VLCAD is directly demonstrated and is required for dimer
      assembly (PMID:9599005); UniProt lists "Mitochondrion inner membrane; Peripheral membrane
      protein".
    supported_by:
    - reference_id: PMID:9599005
      supporting_text: "association of VLCAD protein with mitochondrial inner membrane is necessary for dimer assembly and formation of mature VLCAD"
# --- Annotation 6: fatty acid beta-oxidation (IEA, ARBA) ---
- term:
    id: GO:0006635
    label: fatty acid beta-oxidation
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  qualifier: involved_in
  review:
    summary: >-
      ARBA electronic annotation placing VLCAD in fatty acid beta-oxidation. VLCAD catalyzes the
      first step of this pathway, so the annotation is correct and represents a core biological process.
    action: ACCEPT
    reason: >-
      VLCAD catalyzes the initial step of the mitochondrial beta-oxidation spiral (PMID:9461620);
      loss of VLCAD impairs long-chain fatty acid beta-oxidation (PMID:7668252). Consistent with the
      IDA/IMP annotations to beta-oxidation.
    supported_by:
    - reference_id: PMID:9461620
      supporting_text: "Very long-chain acyl-CoA dehydrogenase (VLCAD) is one of four flavoproteins which catalyze the initial step of the mitochondrial beta-oxidation spiral"
# --- Annotation 7: oxidoreductase activity, CH-CH group (IEA, InterPro) ---
- term:
    id: GO:0016627
    label: oxidoreductase activity, acting on the CH-CH group of donors
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  qualifier: enables
  review:
    summary: >-
      InterPro-based annotation to the intermediate oxidoreductase term. The acyl-CoA dehydrogenase
      reaction introduces a double bond between the alpha and beta carbons, i.e. oxidation of a
      CH-CH group, so this term is accurate at an appropriate intermediate level.
    action: KEEP_AS_NON_CORE
    reason: >-
      Correct intermediate parent between general oxidoreductase activity and the specific acyl-CoA
      dehydrogenase activities, which are the core MF annotations.
    supported_by:
    - reference_id: PMID:9461620
      supporting_text: "the alpha-proton in the alphabeta-dehydrogenation reaction"
# --- Annotation 8: VLCAD activity (IEA, ARBA/Rhea) ---
- term:
    id: GO:0017099
    label: very-long-chain fatty acyl-CoA dehydrogenase activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: enables
  review:
    summary: >-
      Electronic annotation from ARBA/Rhea mapping based on EC 1.3.8.9. This is VLCAD's defining
      catalytic activity and is also supported by direct experimental (IDA) evidence, so the
      electronic call is correct.
    action: ACCEPT
    reason: >-
      EC 1.3.8.9 (very-long-chain acyl-CoA dehydrogenase) was assigned to VLCAD from substrate
      characterization (PMID:21237683); the activity is directly demonstrated (PMID:9461620). Core
      molecular function.
    supported_by:
    - reference_id: PMID:9461620
      supporting_text: "Very long-chain acyl-CoA dehydrogenase (VLCAD) is one of four flavoproteins which catalyze the initial step of the mitochondrial beta-oxidation spiral"
# --- Annotation 9: mitochondrial membrane (IEA, ARBA) ---
- term:
    id: GO:0031966
    label: mitochondrial membrane
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  qualifier: located_in
  review:
    summary: >-
      ARBA electronic annotation to the broader mitochondrial membrane term. VLCAD is a peripheral
      mitochondrial inner-membrane protein, so this term is correct but less specific than the
      inner-membrane annotation.
    action: KEEP_AS_NON_CORE
    reason: >-
      Correct but subsumed by the more specific GO:0005743 (mitochondrial inner membrane).
    supported_by:
    - reference_id: PMID:9599005
      supporting_text: "Mature VLCAD is a homodimer of a 70-kDa protein associated with the mitochondrial membrane"
# --- Annotation 10: FAD binding (IEA, InterPro) ---
- term:
    id: GO:0050660
    label: flavin adenine dinucleotide binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  qualifier: enables
  review:
    summary: >-
      InterPro-based annotation for FAD binding. VLCAD is an FAD-containing flavoprotein; FAD is the
      obligate redox cofactor and FAD-binding residues (e.g. Phe-418) have been mapped. The term is
      correct and corresponds to a core feature of the enzyme.
    action: ACCEPT
    reason: >-
      FAD is the essential cofactor of VLCAD (UniProt COFACTOR: FAD; PMID:18227065, PMID:9461620);
      FAD-binding mutants lose bound FAD and activity (PMID:9461620). Consistent with the IDA
      annotation to this term.
    supported_by:
    - reference_id: PMID:9461620
      supporting_text: "These data suggest that Phe-418 is involved in the binding and subsequent reduction of FAD"
# --- Annotation 11: medium-chain acyl-CoA dehydrogenase activity (IEA, RHEA) ---
- term:
    id: GO:0070991
    label: medium-chain fatty acyl-CoA dehydrogenase activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000116
  qualifier: enables
  review:
    summary: >-
      Electronic annotation from Rhea mapping, derived from in-vitro reactions on shorter
      (dodecanoyl/decadienoyl, C10-C12) acyl-CoA substrates listed in UniProt. VLCAD's physiological
      specificity is for long- and very-long-chain substrates; medium-chain activity is a minor
      in-vitro property and is the dedicated role of MCAD in vivo.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Assigning a medium-chain ACAD activity to VLCAD over-states its specificity. VLCAD "acts
      specifically on fatty acyl-CoAs with saturated 12 to 24 carbons long primary chains" (UniProt
      FUNCTION); medium-chain oxidation is physiologically handled by MCAD. The Rhea-derived term
      reflects catalytic promiscuity at chain-length boundaries rather than a genuine medium-chain role.
    supported_by:
    - reference_id: PMID:21237683
      supporting_text: "Identification and characterization of new long chain acyl-CoA dehydrogenases"
# --- Annotation 12: protein binding (IPI, HuRI) ---
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:32296183
  qualifier: enables
  review:
    summary: >-
      IPI annotation from the HuRI binary interactome (yeast two-hybrid) recording a single
      interaction with TAF1B (Q53T94, an RNA polymerase I transcription factor). The generic
      "protein binding" term is uninformative, and a binary interaction between a mitochondrial
      inner-membrane FAO enzyme and a nucleolar Pol I factor is most likely a high-throughput
      artifact without established biological relevance.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      "Protein binding" carries no functional information, and the underlying single Y2H interaction
      (with TAF1B) has no demonstrated physiological context for VLCAD. The biologically meaningful
      interaction of VLCAD is homodimerization, captured by GO:0042802.
    supported_by:
    - reference_id: PMID:32296183
      supporting_text: "a human 'all-by-all' reference interactome map of human binary protein interactions"
# --- Annotation 13: temperature homeostasis (IEA, Ensembl from mouse) ---
- term:
    id: GO:0001659
    label: temperature homeostasis
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: >-
      Electronic annotation transferred via Ensembl Compara from mouse UniProtKB:P50544, which is
      the mouse long-chain acyl-CoA dehydrogenase (Acadl/LCAD), not a VLCAD ortholog. The
      thermoregulation phenotype derives from the LCAD-knockout mouse and is not a demonstrated
      function of human VLCAD.
    action: REMOVE
    reason: >-
      The source protein P50544 is mouse LCAD (ACADL ortholog), so this is a cross-paralog
      mis-transfer of an LCAD-knockout whole-organism phenotype onto human ACADVL. Temperature
      homeostasis is not a function of human VLCAD; the human ortholog of mouse Acadl is ACADL.
    supported_by:
    - reference_id: PMID:21237683
      supporting_text: "Identification and characterization of new long chain acyl-CoA dehydrogenases"
# --- Annotation 14: FAO using ACAD (IEA, Ensembl from mouse) ---
- term:
    id: GO:0033539
    label: fatty acid beta-oxidation using acyl-CoA dehydrogenase
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: >-
      Electronic annotation transferred from mouse P50544. Although the source is the mouse LCAD
      ortholog, the specific process (beta-oxidation using an acyl-CoA dehydrogenase) is exactly
      what VLCAD performs, so the term is biologically correct for ACADVL and is also supported by
      direct experimental annotations (IMP/IDA) to this same term.
    action: ACCEPT
    reason: >-
      VLCAD catalyzes the acyl-CoA dehydrogenase step of mitochondrial beta-oxidation; this term is
      correct regardless of the ortholog-transfer source and corroborated by PMID:9599005 (IMP) and
      PMID:7668252 (IDA).
    supported_by:
    - reference_id: PMID:9461620
      supporting_text: "the initial step of the mitochondrial beta-oxidation spiral"
# --- Annotation 15: negative regulation of fatty acid biosynthetic process (IEA, mouse) ---
- term:
    id: GO:0045717
    label: negative regulation of fatty acid biosynthetic process
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: >-
      Electronic annotation transferred via Ensembl Compara from mouse UniProtKB:P50544 (mouse
      LCAD/Acadl). This regulatory phenotype comes from LCAD-knockout mouse studies and is not a
      demonstrated function of human VLCAD.
    action: REMOVE
    reason: >-
      Cross-paralog mis-transfer from mouse LCAD (P50544). Regulation of fatty acid biosynthesis is
      not an established VLCAD function; VLCAD is a catabolic dehydrogenase, and this whole-organism
      regulatory phenotype belongs to LCAD biology in mouse.
    supported_by:
    - reference_id: PMID:21237683
      supporting_text: "Long-chain fatty acids are an important source of energy in muscle and heart"
# --- Annotation 16: negative regulation of fatty acid oxidation (IEA, mouse) ---
- term:
    id: GO:0046322
    label: negative regulation of fatty acid oxidation
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: >-
      Electronic annotation transferred from mouse P50544 (LCAD). VLCAD is a positive effector of
      fatty acid oxidation (it catalyzes a beta-oxidation step), so annotating it to NEGATIVE
      regulation of fatty acid oxidation by ortholog transfer is biologically inconsistent.
    action: REMOVE
    reason: >-
      Cross-paralog mis-transfer from mouse LCAD; the term is also internally contradictory for a
      catabolic dehydrogenase that drives, rather than negatively regulates, fatty acid oxidation.
    supported_by:
    - reference_id: PMID:21237683
      supporting_text: "the acyl-CoA dehydrogenases (ACADs) participate in consecutive cycles of"
# --- Annotation 17: regulation of cholesterol metabolic process (IEA, mouse) ---
- term:
    id: GO:0090181
    label: regulation of cholesterol metabolic process
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: >-
      Electronic annotation transferred from mouse P50544 (LCAD). The cholesterol-metabolism
      phenotype derives from LCAD-knockout mouse studies and is not a demonstrated function of
      human VLCAD.
    action: REMOVE
    reason: >-
      Cross-paralog mis-transfer from mouse LCAD (P50544). Regulation of cholesterol metabolism is
      not an established VLCAD function; the human ortholog of mouse Acadl is ACADL, not ACADVL.
    supported_by:
    - reference_id: PMID:21237683
      supporting_text: "the synthesis and/or degradation of unique cellular lipids"
# --- Annotation 18: mitochondrion (IDA, HPA) ---
- term:
    id: GO:0005739
    label: mitochondrion
  evidence_type: IDA
  original_reference_id: GO_REF:0000052
  qualifier: located_in
  review:
    summary: >-
      IDA annotation from HPA immunofluorescence. Mitochondrial localization of VLCAD is
      well-established; this is correct but less specific than the inner-membrane annotation.
    action: KEEP_AS_NON_CORE
    reason: >-
      Correct mitochondrial localization, subsumed by the more specific GO:0005743 inner-membrane
      annotation supported by PMID:9599005.
    supported_by:
    - reference_id: PMID:9599005
      supporting_text: "associated with the mitochondrial membrane"
# --- Annotation 19: mitochondrion (HTP, proteome) ---
- term:
    id: GO:0005739
    label: mitochondrion
  evidence_type: HTP
  original_reference_id: PMID:34800366
  qualifier: located_in
  review:
    summary: >-
      High-throughput annotation from a quantitative high-confidence human mitochondrial proteome
      study. VLCAD is a well-established mitochondrial protein; this corroborates targeted studies.
    action: KEEP_AS_NON_CORE
    reason: >-
      Correct mitochondrial localization from proteomics, subsumed by the specific inner-membrane
      annotation. Consistent with the broader body of evidence.
    supported_by:
    - reference_id: PMID:34800366
      supporting_text: "Quantitative high-confidence human mitochondrial proteome and its dynamics"
# --- Annotation 20: acyl-CoA dehydrogenase activity (IMP, PMID:9599005) ---
- term:
    id: GO:0003995
    label: acyl-CoA dehydrogenase activity
  evidence_type: IMP
  original_reference_id: PMID:9599005
  qualifier: enables
  review:
    summary: >-
      IMP annotation based on the monomeric disease mutant S583W, which fails to assemble into the
      active membrane-bound dimer (PMID:9599005). The mutant phenotype implicates VLCAD's
      dehydrogenase activity, though "acyl-CoA dehydrogenase activity" is the general parent of the
      more specific VLCAD/LCAD terms.
    action: KEEP_AS_NON_CORE
    reason: >-
      Legitimate experimental annotation (mutant assembly defect linked to enzyme function), but at
      the general ACAD level it is subsumed by the specific GO:0017099/GO:0004466 activities.
    supported_by:
    - reference_id: PMID:9599005
      supporting_text: "a VLCAD monomeric mutant S583W, a novel mutation identified from a patient with VLCAD deficiency, did not associate with the mitochondrial membrane after import"
# --- Annotation 21: FAO using ACAD (IMP, PMID:9599005) ---
- term:
    id: GO:0033539
    label: fatty acid beta-oxidation using acyl-CoA dehydrogenase
  evidence_type: IMP
  original_reference_id: PMID:9599005
  qualifier: involved_in
  review:
    summary: >-
      IMP annotation linking the VLCAD assembly/function defect (S583W) to its role in fatty acid
      beta-oxidation. This is a core biological process and is supported by patient-derived mutation
      data demonstrating that defective VLCAD impairs the pathway.
    action: ACCEPT
    reason: >-
      VLCAD is required for the acyl-CoA dehydrogenase step of beta-oxidation; the disease-causing
      monomeric mutant connects loss of VLCAD function to the pathway (PMID:9599005), corroborated
      by flux restoration in PMID:7668252.
    supported_by:
    - reference_id: PMID:9599005
      supporting_text: "a VLCAD monomeric mutant S583W, a novel mutation identified from a patient with VLCAD deficiency"
# --- Annotation 22: identical protein binding (IDA, PMID:9599005) ---
- term:
    id: GO:0042802
    label: identical protein binding
  evidence_type: IDA
  original_reference_id: PMID:9599005
  qualifier: enables
  review:
    summary: >-
      IDA annotation capturing VLCAD homodimerization. PMID:9599005 directly demonstrated that
      mature VLCAD is a homodimer and characterized the membrane-dependent dimer-assembly process.
      Unlike generic "protein binding", this term is informative about the functional quaternary
      structure, though "identical protein binding" describes self-association rather than a
      catalytic molecular function.
    action: KEEP_AS_NON_CORE
    reason: >-
      VLCAD is an obligate homodimer; dimerization is required to form the mature active enzyme and
      a monomeric mutant (S583W) is disease-causing (PMID:9599005). Retained as a real,
      disease-relevant but non-core assembly property (the core MF is the dehydrogenase activity).
      Kept consistent with the parallel homo-oligomer annotation on ACADM GO:0042802, which is
      likewise KEEP_AS_NON_CORE.
    supported_by:
    - reference_id: PMID:9599005
      supporting_text: "Mature VLCAD is a homodimer of a 70-kDa protein associated with the mitochondrial membrane"
# --- Annotation 23: acyl-CoA dehydrogenase activity (IMP, PMID:9461620) ---
- term:
    id: GO:0003995
    label: acyl-CoA dehydrogenase activity
  evidence_type: IMP
  original_reference_id: PMID:9461620
  qualifier: enables
  review:
    summary: >-
      IMP annotation based on catalytic and FAD-binding mutants (E422Q catalytic-base mutant;
      F418 FAD-binding mutants) that abolish or impair dehydrogenase activity (PMID:9461620). This
      experimentally establishes VLCAD's enzymatic activity at the general ACAD level.
    action: KEEP_AS_NON_CORE
    reason: >-
      Strong experimental support for VLCAD enzymatic activity via active-site mutagenesis, but the
      general ACAD term is subsumed by the specific GO:0017099/GO:0004466 activities used as core.
    supported_by:
    - reference_id: PMID:9461620
      supporting_text: "Replacing Glu-422 with glutamine (E422Q) caused a loss of enzyme activity"
# --- Annotation 24: mitochondrion (IDA, PMID:9461620) ---
- term:
    id: GO:0005739
    label: mitochondrion
  evidence_type: IDA
  original_reference_id: PMID:9461620
  qualifier: located_in
  review:
    summary: >-
      IDA annotation for mitochondrial localization from the catalytic/FAD-binding residue study.
      Correct but less specific than the inner-membrane localization.
    action: KEEP_AS_NON_CORE
    reason: >-
      Correct mitochondrial localization, subsumed by the specific GO:0005743 inner-membrane
      annotation (PMID:9599005).
    supported_by:
    - reference_id: PMID:9599005
      supporting_text: "associated with the mitochondrial membrane"
# --- Annotation 25: VLCAD activity (IDA, PMID:9461620) ---
- term:
    id: GO:0017099
    label: very-long-chain fatty acyl-CoA dehydrogenase activity
  evidence_type: IDA
  original_reference_id: PMID:9461620
  qualifier: enables
  review:
    summary: >-
      IDA annotation for the defining very-long-chain acyl-CoA dehydrogenase activity, supported by
      direct enzymatic characterization of recombinant VLCAD and its catalytic/FAD-binding mutants
      (PMID:9461620). This is the core molecular function.
    action: ACCEPT
    reason: >-
      VLCAD's very-long-chain acyl-CoA dehydrogenase activity is directly demonstrated; the
      catalytic Glu-422 and FAD-binding Phe-418 were mapped by mutagenesis (PMID:9461620).
    supported_by:
    - reference_id: PMID:9461620
      supporting_text: "Very long-chain acyl-CoA dehydrogenase (VLCAD) is one of four flavoproteins which catalyze the initial step of the mitochondrial beta-oxidation spiral"
# --- Annotation 26: identical protein binding (IDA, PMID:9461620) ---
- term:
    id: GO:0042802
    label: identical protein binding
  evidence_type: IDA
  original_reference_id: PMID:9461620
  qualifier: enables
  review:
    summary: >-
      IDA annotation reflecting VLCAD homodimerization, characterized as part of the recombinant
      enzyme studies (the protein is a homodimer; PMID:9461620, UniProt SUBUNIT). Informative about
      quaternary structure rather than a generic interaction.
    action: KEEP_AS_NON_CORE
    reason: >-
      VLCAD functions as a homodimer (UniProt SUBUNIT lists PMID:9461620 among the supporting
      references); dimerization is a defining structural feature of the active enzyme, but
      "identical protein binding" is a non-core assembly property rather than the core catalytic
      MF. Consistent with the second GO:0042802 annotation above and with ACADM.
    supported_by:
    - reference_id: PMID:9599005
      supporting_text: "Mature VLCAD is a homodimer of a 70-kDa protein associated with the mitochondrial membrane"
# --- Annotation 27: FAD binding (IDA, PMID:9461620) ---
- term:
    id: GO:0050660
    label: flavin adenine dinucleotide binding
  evidence_type: IDA
  original_reference_id: PMID:9461620
  qualifier: enables
  review:
    summary: >-
      IDA annotation for FAD binding, directly supported by the demonstration that FAD-binding
      mutants (F418L/F418V) contain no bound FAD and that Phe-418 is required for FAD binding and
      reduction (PMID:9461620). FAD is the obligate cofactor.
    action: ACCEPT
    reason: >-
      Direct experimental evidence that VLCAD binds FAD as its redox cofactor and that loss of FAD
      destabilizes the protein (PMID:9461620). Core molecular function feature.
    supported_by:
    - reference_id: PMID:9461620
      supporting_text: "F418L and F418V contained no bound FAD when expressed at extremely high levels in the baculovirus expression system"
# --- Annotation 28: long-chain acyl-CoA dehydrogenase activity (IDA, PMID:7668252) ---
- term:
    id: GO:0004466
    label: long-chain fatty acyl-CoA dehydrogenase activity
  evidence_type: IDA
  original_reference_id: PMID:7668252
  qualifier: enables
  review:
    summary: >-
      IDA annotation from the original cloning/characterization paper, which demonstrated that VLCAD
      drives long-chain (palmitic acid) beta-oxidation flux: restoring VLCAD activity in patient
      fibroblasts restored palmitate beta-oxidation (PMID:7668252). VLCAD's long-chain acyl-CoA
      dehydrogenase activity is a core function.
    action: ACCEPT
    reason: >-
      Direct functional evidence that VLCAD provides long-chain acyl-CoA dehydrogenase activity
      (palmitoyl-CoA, C16) in human cells (PMID:7668252).
    supported_by:
    - reference_id: PMID:7668252
      supporting_text: "raising VLCAD activity to approximately 20% of normal control fibroblast activity raised palmitic acid beta-oxidation flux to the level found in control fibroblasts"
# --- Annotation 29: mitochondrial membrane (IDA, PMID:16020546) ---
- term:
    id: GO:0031966
    label: mitochondrial membrane
  evidence_type: IDA
  original_reference_id: PMID:16020546
  qualifier: located_in
  review:
    summary: >-
      IDA annotation to mitochondrial membrane. PMID:16020546 is primarily a study of the paralog
      ACAD9 (Ensenauer et al. 2005); its membrane-fractionation result concerns ACAD-9. VLCAD is,
      however, independently and robustly established as a peripheral mitochondrial inner-membrane
      protein (PMID:9599005), so the term itself is correct for VLCAD even though this particular
      reference is paralog-focused.
    action: KEEP_AS_NON_CORE
    reason: >-
      The membrane localization is correct for VLCAD but is better supported by VLCAD-specific data
      (PMID:9599005) and is subsumed by the inner-membrane annotation. Retained as non-core rather
      than removed, since VLCAD membrane localization is genuine and the curator may have used
      VLCAD-relevant content not in the cached abstract.
    supported_by:
    - reference_id: PMID:9599005
      supporting_text: "Mature VLCAD is a homodimer of a 70-kDa protein associated with the mitochondrial membrane"
# --- Annotation 30: FAO using ACAD (IDA, PMID:7668252) ---
- term:
    id: GO:0033539
    label: fatty acid beta-oxidation using acyl-CoA dehydrogenase
  evidence_type: IDA
  original_reference_id: PMID:7668252
  qualifier: involved_in
  review:
    summary: >-
      IDA annotation linking VLCAD to the acyl-CoA dehydrogenase step of beta-oxidation, supported
      by the demonstration that VLCAD activity drives long-chain fatty acid beta-oxidation flux in
      human fibroblasts (PMID:7668252). Core biological process.
    action: ACCEPT
    reason: >-
      VLCAD-dependent restoration of palmitate beta-oxidation directly demonstrates its role in this
      process (PMID:7668252).
    supported_by:
    - reference_id: PMID:7668252
      supporting_text: "the deficiency of the normal VLCAD protein causes impaired long-chain fatty acid beta-oxidation activity in the patients' fibroblasts"
# --- Annotation 31: epithelial cell differentiation (IEP, PMID:21492153) ---
- term:
    id: GO:0030855
    label: epithelial cell differentiation
  evidence_type: IEP
  original_reference_id: PMID:21492153
  qualifier: involved_in
  review:
    summary: >-
      IEP annotation from a Caco-2 differentiation proteomics screen in which lipid-metabolism
      proteins (including VLCAD) were up-regulated upon enterocyte differentiation (PMID:21492153).
      This is a correlative expression change during differentiation, not evidence that VLCAD has a
      role in driving epithelial cell differentiation.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Up-regulation of a metabolic enzyme during a differentiation time course reflects altered
      metabolic demand, not a function of VLCAD in differentiation. No mechanistic link supports an
      involved_in relationship to epithelial cell differentiation.
    supported_by:
    - reference_id: PMID:21492153
      supporting_text: "proteins involved in xenobiotic and drug metabolism as well as in lipid metabolism were upregulated upon cellular differentiation"
# --- Annotation 32: mitochondrial matrix (TAS, Reactome 1791069) ---
- term:
    id: GO:0005759
    label: mitochondrial matrix
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-1791069
  qualifier: located_in
  review:
    summary: >-
      TAS annotation from Reactome, which places the beta-oxidation reactions in the matrix
      compartment. VLCAD is a peripheral inner-membrane protein with its catalytic face toward the
      matrix; the mature dimer is membrane-associated rather than freely soluble in the matrix.
    action: KEEP_AS_NON_CORE
    reason: >-
      The matrix annotation is a reasonable compartmental placement (matrix-facing activity) but is
      less accurate than the experimentally determined inner-membrane localization (PMID:9599005);
      retained as non-core.
    supported_by:
    - reference_id: PMID:9599005
      supporting_text: "association of VLCAD protein with mitochondrial inner membrane is necessary for dimer assembly"
# --- Annotation 33: mitochondrial matrix (TAS, Reactome 77299) ---
- term:
    id: GO:0005759
    label: mitochondrial matrix
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-77299
  qualifier: located_in
  review:
    summary: >-
      TAS annotation from the Reactome reaction palmitoyl-CoA + FAD => trans-hexadec-2-enoyl-CoA +
      FADH2, placed in the mitochondrial matrix. This is the VLCAD-catalyzed dehydrogenation step;
      the compartment is matrix-facing, though the enzyme is inner-membrane-associated.
    action: KEEP_AS_NON_CORE
    reason: >-
      Correct as a matrix-facing compartmental placement of the VLCAD reaction, but less precise
      than the inner-membrane annotation; retained as non-core.
    supported_by:
    - reference_id: PMID:9599005
      supporting_text: "associated with the mitochondrial membrane"
# --- Annotation 34: regulation of cholesterol metabolic process (ISS, mouse) ---
- term:
    id: GO:0090181
    label: regulation of cholesterol metabolic process
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  qualifier: involved_in
  review:
    summary: >-
      ISS annotation transferred by sequence similarity from mouse UniProtKB:P50544 (mouse LCAD,
      the ACADL ortholog). The cholesterol-metabolism phenotype derives from LCAD-knockout mouse
      biology and is not a demonstrated function of human VLCAD.
    action: REMOVE
    reason: >-
      Cross-paralog mis-transfer from mouse LCAD (P50544); the human ortholog of mouse Acadl is
      ACADL, not ACADVL. Regulation of cholesterol metabolism is not an established VLCAD function.
    supported_by:
    - reference_id: PMID:21237683
      supporting_text: "the synthesis and/or degradation of unique cellular lipids"
# --- Annotation 35: temperature homeostasis (ISS, mouse) ---
- term:
    id: GO:0001659
    label: temperature homeostasis
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  qualifier: involved_in
  review:
    summary: >-
      ISS annotation transferred by sequence similarity from mouse UniProtKB:P50544 (mouse LCAD).
      The thermoregulation phenotype is from the LCAD-knockout mouse and is not a demonstrated
      function of human VLCAD.
    action: REMOVE
    reason: >-
      Cross-paralog mis-transfer from mouse LCAD (P50544). Temperature homeostasis is an LCAD-knockout
      mouse phenotype, not a function of human VLCAD; the correct human ortholog is ACADL.
    supported_by:
    - reference_id: PMID:21237683
      supporting_text: "Long-chain fatty acids are an important source of energy in muscle and heart"
# --- Annotation 36: mitochondrion (ISS, mouse) ---
- term:
    id: GO:0005739
    label: mitochondrion
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  qualifier: located_in
  review:
    summary: >-
      ISS annotation for mitochondrial localization transferred from mouse P50544. Although the
      source is the LCAD ortholog, the mitochondrial localization is unquestionably correct for
      human VLCAD and corroborated by direct experimental data.
    action: KEEP_AS_NON_CORE
    reason: >-
      Mitochondrial localization is correct for VLCAD (PMID:9599005, PMID:34800366) and subsumed by
      the specific inner-membrane annotation; retained as non-core despite the ortholog-transfer source.
    supported_by:
    - reference_id: PMID:9599005
      supporting_text: "associated with the mitochondrial membrane"
# --- Annotation 37: FAO using ACAD (ISS, mouse) ---
- term:
    id: GO:0033539
    label: fatty acid beta-oxidation using acyl-CoA dehydrogenase
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  qualifier: involved_in
  review:
    summary: >-
      ISS annotation transferred from mouse P50544. Despite the LCAD-ortholog source, the process
      (beta-oxidation via an acyl-CoA dehydrogenase) is precisely what VLCAD performs and is
      independently supported by experimental annotations.
    action: ACCEPT
    reason: >-
      VLCAD catalyzes the acyl-CoA dehydrogenase step of beta-oxidation (PMID:9461620); the term is
      biologically correct for ACADVL irrespective of the transfer source and is corroborated by
      IMP/IDA evidence.
    supported_by:
    - reference_id: PMID:9461620
      supporting_text: "the initial step of the mitochondrial beta-oxidation spiral"
# --- Annotation 38: negative regulation of fatty acid biosynthetic process (ISS, mouse) ---
- term:
    id: GO:0045717
    label: negative regulation of fatty acid biosynthetic process
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  qualifier: involved_in
  review:
    summary: >-
      ISS annotation transferred by sequence similarity from mouse P50544 (mouse LCAD). The
      regulatory phenotype is from LCAD-knockout mouse studies and is not a demonstrated function
      of human VLCAD.
    action: REMOVE
    reason: >-
      Cross-paralog mis-transfer from mouse LCAD; regulation of fatty acid biosynthesis is not an
      established VLCAD function and the correct human ortholog of mouse Acadl is ACADL.
    supported_by:
    - reference_id: PMID:21237683
      supporting_text: "Long-chain fatty acids are an important source of energy in muscle and heart"
# --- Annotation 39: negative regulation of fatty acid oxidation (ISS, mouse) ---
- term:
    id: GO:0046322
    label: negative regulation of fatty acid oxidation
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  qualifier: involved_in
  review:
    summary: >-
      ISS annotation transferred from mouse P50544 (LCAD). VLCAD positively drives fatty acid
      oxidation by catalyzing a beta-oxidation step, so annotating it to NEGATIVE regulation of
      fatty acid oxidation by ortholog transfer is biologically inconsistent.
    action: REMOVE
    reason: >-
      Cross-paralog mis-transfer from mouse LCAD and internally contradictory for a catabolic
      dehydrogenase that promotes, rather than negatively regulates, fatty acid oxidation.
    supported_by:
    - reference_id: PMID:21237683
      supporting_text: "the acyl-CoA dehydrogenases (ACADs) participate in consecutive cycles of"
# --- Annotation 40: mitochondrial nucleoid (IDA, PMID:18063578) ---
- term:
    id: GO:0042645
    label: mitochondrial nucleoid
  evidence_type: IDA
  original_reference_id: PMID:18063578
  qualifier: located_in
  review:
    summary: >-
      IDA annotation from a mitochondrial-nucleoid proteomics study. VLCAD (like other metabolic
      enzymes) co-purified with native nucleoid preparations but such metabolic proteins "were not
      observed to cross-link to mtDNA", indicating peripheral co-purification rather than genuine
      nucleoid residence (PMID:18063578).
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Co-purification with biochemically isolated nucleoids does not establish nucleoid
      localization; the study explicitly notes these metabolic proteins do not cross-link to mtDNA
      and likely reside in the peripheral region. VLCAD's established localization is the inner
      membrane (PMID:9599005).
    supported_by:
    - reference_id: PMID:18063578
      supporting_text: "Several other metabolic proteins and chaperones identified in native nucleoids, including ATAD3, were not observed to cross-link to mtDNA"
# --- Annotation 41: long-chain acyl-CoA dehydrogenase activity (TAS, PMID:8466512) ---
- term:
    id: GO:0004466
    label: long-chain fatty acyl-CoA dehydrogenase activity
  evidence_type: TAS
  original_reference_id: PMID:8466512
  qualifier: enables
  review:
    summary: >-
      TAS annotation from the report that first defined VLCAD deficiency as a disease, using very
      low palmitoyl-CoA (C16, long-chain) dehydrogenase activity and loss of anti-VLCAD
      immunoreactivity in patients (PMID:8466512). Supports VLCAD's long-chain acyl-CoA
      dehydrogenase activity.
    action: ACCEPT
    reason: >-
      Patient deficiency of palmitoyl-CoA dehydrogenase activity attributable to VLCAD directly
      supports the long-chain acyl-CoA dehydrogenase activity assignment (PMID:8466512).
    supported_by:
    - reference_id: PMID:8466512
      supporting_text: "found to have a novel disease, VLCAD deficiency, as judged from the results of very low palmitoyl-CoA dehydrogenase activity and the lack of immunoreactivity toward antibody raised to purified VLCAD"
# --- Annotation 42: energy derivation by oxidation of organic compounds (TAS, PMID:7479827) ---
- term:
    id: GO:0015980
    label: energy derivation by oxidation of organic compounds
  evidence_type: TAS
  original_reference_id: PMID:7479827
  qualifier: involved_in
  review:
    summary: >-
      TAS annotation reflecting VLCAD's role in supplying energy through long-chain fatty acid
      oxidation, particularly in the heart. VLCAD deficiency reduces myocardial beta-oxidation and
      energy production (PMID:7479827). This is a correct higher-level biological process.
    action: KEEP_AS_NON_CORE
    reason: >-
      Accurate but broad parent process; VLCAD's specific contribution is better captured by the
      fatty acid beta-oxidation terms. The energy-derivation role is well supported by the cardiac
      phenotype (PMID:7479827).
    supported_by:
    - reference_id: PMID:7479827
      supporting_text: "VLCAD deficiency reduces myocardial fatty acid beta-oxidation and energy production and is associated with cardiomyopathy and sudden death in childhood"
core_functions:
- description: >-
    Very-long-chain/long-chain acyl-CoA dehydrogenase activity: VLCAD catalyzes the FAD-dependent,
    stereospecific alpha,beta-dehydrogenation of very-long-chain and long-chain acyl-CoA thioesters
    (C12-C24, e.g. palmitoyl-CoA), the first and committed step of each cycle of mitochondrial fatty
    acid beta-oxidation, transferring electrons to the electron-transfer flavoprotein (ETF).
  molecular_function:
    id: GO:0017099
    label: very-long-chain fatty acyl-CoA dehydrogenase activity
  directly_involved_in:
  - id: GO:0006635
    label: fatty acid beta-oxidation
  locations:
  - id: GO:0005743
    label: mitochondrial inner membrane
  supported_by:
  - reference_id: PMID:9461620
    supporting_text: "Very long-chain acyl-CoA dehydrogenase (VLCAD) is one of four flavoproteins which catalyze the initial step of the mitochondrial beta-oxidation spiral"
  - reference_id: PMID:7668252
    supporting_text: "raising VLCAD activity to approximately 20% of normal control fibroblast activity raised palmitic acid beta-oxidation flux to the level found in control fibroblasts"
- description: >-
    FAD cofactor binding: VLCAD binds FAD as its obligate redox prosthetic group; the bound flavin
    is reduced during substrate dehydrogenation and is required for both catalysis and structural
    stability of the subunit.
  molecular_function:
    id: GO:0050660
    label: flavin adenine dinucleotide binding
  directly_involved_in:
  - id: GO:0006635
    label: fatty acid beta-oxidation
  locations:
  - id: GO:0005743
    label: mitochondrial inner membrane
  supported_by:
  - reference_id: PMID:9461620
    supporting_text: "These data suggest that Phe-418 is involved in the binding and subsequent reduction of FAD"
proposed_new_terms: []
suggested_questions:
- question: >-
    Several whole-organism regulatory annotations on human ACADVL (temperature homeostasis,
    regulation of cholesterol metabolism, negative regulation of fatty acid biosynthesis/oxidation)
    were transferred by ortholog/sequence similarity from mouse P50544, which is LCAD (Acadl), not a
    VLCAD ortholog. Should these be reassigned to ACADL and removed from ACADVL?
- question: >-
    What is the precise topology and functional consequence of VLCAD's inner-membrane association?
    Does membrane binding contribute to substrate channeling from the carnitine shuttle/CPT system,
    beyond its established requirement for dimer assembly?
suggested_experiments:
- description: >-
    Determine the in-vivo substrate-chain-length profile of human VLCAD across heart, skeletal
    muscle, liver and brain using stable-isotope acylcarnitine flux assays in tissue-specific
    knockdown models, to define where VLCAD versus ACAD9/ACAD11/LCAD dominates long-chain FAO.
  hypothesis: >-
    VLCAD is the principal long-chain acyl-CoA dehydrogenase in heart and skeletal muscle, whereas
    ACAD9/ACAD11 dominate in brain, explaining the cardiac/muscle-restricted disease phenotype.
- description: >-
    Reconstitute VLCAD with ETF and test whether inner-membrane association modulates electron
    transfer efficiency to ETF/ETF-QO, comparing membrane-bound dimer to the soluble monomeric
    S583W mutant.
  hypothesis: >-
    Membrane-associated VLCAD dimers couple more efficiently to ETF-dependent electron transfer than
    the assembly-defective monomeric mutant, linking quaternary/membrane state to catalytic output.
references:
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with GO terms
  findings: []
- id: GO_REF:0000024
  title: Manual transfer of experimentally-verified manual GO annotation data to orthologs
    by curator judgment of sequence similarity
  findings: []
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000044
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location
    vocabulary mapping, accompanied by conservative changes to GO terms applied by
    UniProt
  findings: []
- id: GO_REF:0000052
  title: Gene Ontology annotation based on curation of immunofluorescence data
  findings: []
- id: GO_REF:0000107
  title: Automatic transfer of experimentally verified manual GO annotation data to
    orthologs using Ensembl Compara
  findings: []
- id: GO_REF:0000116
  title: Automatic Gene Ontology annotation based on Rhea mapping
  findings: []
- id: GO_REF:0000117
  title: Electronic Gene Ontology annotations created by ARBA machine learning models
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings: []
- id: PMID:16020546
  title: Human acyl-CoA dehydrogenase-9 plays a novel role in the mitochondrial beta-oxidation
    of unsaturated fatty acids.
  findings:
  - statement: >-
      Primarily characterizes the paralog ACAD9 (membrane-associated mitochondrial ACAD with
      long-chain activity). Used in GOA to support a mitochondrial-membrane localization annotation
      on ACADVL; VLCAD inner-membrane localization is independently established by PMID:9599005.
  reference_review:
    relevance: LOW
    correctness: MISCITED
    review_notes: >-
      This is the ACAD9 (Ensenauer 2005) paper; its membrane-fractionation data concern ACAD-9, not
      VLCAD. The mitochondrial-membrane term it is cited for is nonetheless correct for VLCAD on
      independent grounds, so the annotation was kept as non-core rather than removed.
- id: PMID:18063578
  title: The layered structure of human mitochondrial DNA nucleoids.
  findings:
  - statement: >-
      Mitochondrial-nucleoid proteomics. Metabolic enzymes including VLCAD co-purified with native
      nucleoids but did not cross-link to mtDNA, indicating peripheral co-purification rather than
      genuine nucleoid localization.
    supporting_text: >-
      Several other metabolic proteins and chaperones identified in native nucleoids, including
      ATAD3, were not observed to cross-link to mtDNA.
  reference_review:
    relevance: LOW
    correctness: MISCITED
    review_notes: >-
      Supports co-purification with nucleoid preparations but the paper itself states these
      metabolic proteins do not cross-link mtDNA; cited for a nucleoid-localization annotation that
      is best treated as an over-annotation.
- id: PMID:18227065
  title: 'Structural basis for substrate fatty acyl chain specificity: crystal structure of
    human very-long-chain acyl-CoA dehydrogenase.'
  findings:
  - statement: >-
      Crystal structure of human VLCAD. Defines the long substrate-binding tunnel that
      accommodates very-long-chain acyl-CoA substrates (the structural basis of VLCAD's
      chain-length specificity), the bound FAD cofactor at the isoalloxazine re-face, and the
      catalytic base Glu-422. Referenced in the FAD-binding annotation review.
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: >-
      PubMed-verified crystal-structure paper for human VLCAD; directly supports the FAD-binding
      and very-long-chain substrate-specificity annotations.
- id: PMID:21237683
  title: Identification and characterization of new long chain acyl-CoA dehydrogenases.
  findings:
  - statement: >-
      Characterizes ACAD9/ACAD10/ACAD11 and assigns EC 1.3.8.9 (very-long-chain) for VLCAD via
      substrate characterization. Shows that in human cerebellum the long-chain FAO spectrum is
      covered by ACAD9/ACAD11 rather than VLCAD, indicating tissue-specific division of labor.
    supporting_text: >-
      The combination of ACAD11 with the newly characterized ACAD9 accommodates the full spectrum
      of long chain fatty acid substrates presented to mitochondrial β-oxidation in human cerebellum.
  reference_review:
    relevance: MEDIUM
    correctness: VERIFIED
    review_notes: >-
      PubMed-verified. Primarily about ACAD9/10/11 but provides the substrate-based EC 1.3.8.9
      assignment context for VLCAD and the tissue-distribution contrast.
- id: PMID:21492153
  title: Analysis of proteomic changes induced upon cellular differentiation of the
    human intestinal cell line Caco-2.
  findings:
  - statement: >-
      Caco-2 differentiation proteomics showing up-regulation of lipid-metabolism proteins
      (including VLCAD) during enterocyte differentiation. Provides only correlative expression
      data, not a functional role in differentiation.
    supporting_text: >-
      proteins involved in xenobiotic and drug metabolism as well as in lipid metabolism were
      upregulated upon cellular differentiation
  reference_review:
    relevance: LOW
    correctness: MISCITED
    review_notes: >-
      PubMed-verified screen, but it supports only a correlative expression change; cited for an
      epithelial-cell-differentiation IEP that over-states VLCAD's role.
- id: PMID:32296183
  title: A reference map of the human binary protein interactome.
  findings:
  - statement: >-
      HuRI binary (Y2H) interactome. Source of a single ACADVL-TAF1B interaction underlying a
      generic protein-binding annotation; no established biological relevance for VLCAD.
    supporting_text: >-
      a human 'all-by-all' reference interactome map of human binary protein interactions
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: >-
      PubMed-verified high-throughput interactome. The cited interaction (with the Pol I factor
      TAF1B) is most plausibly a screening artifact for a mitochondrial inner-membrane enzyme;
      the "protein binding" annotation is uninformative.
- id: PMID:34800366
  title: Quantitative high-confidence human mitochondrial proteome and its dynamics
    in cellular context.
  findings:
  - statement: >-
      Defines a high-confidence human mitochondrial proteome (MitoCoP) in which VLCAD is included,
      corroborating its mitochondrial localization.
    supporting_text: >-
      Quantitative high-confidence human mitochondrial proteome and its dynamics
  reference_review:
    relevance: MEDIUM
    correctness: VERIFIED
    review_notes: >-
      PubMed-verified proteomics resource confirming VLCAD mitochondrial localization.
- id: PMID:7479827
  title: Molecular basis of human mitochondrial very-long-chain acyl-CoA dehydrogenase
    deficiency causing cardiomyopathy and sudden death in childhood.
  findings:
  - statement: >-
      VLCAD catalyzes the first step of beta-oxidation of long-chain fatty acids, the major energy
      source in heart; VLCAD deficiency reduces myocardial beta-oxidation and energy production and
      causes cardiomyopathy and sudden death.
    supporting_text: >-
      VLCAD deficiency reduces myocardial fatty acid beta-oxidation and energy production and is
      associated with cardiomyopathy and sudden death in childhood
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: >-
      PubMed-verified. Establishes the energy-derivation/cardiac role and disease mechanism of VLCAD.
- id: PMID:7668252
  title: Cloning of human very-long-chain acyl-coenzyme A dehydrogenase and molecular
    characterization of its deficiency in two patients.
  findings:
  - statement: >-
      Original cloning of human VLCAD (655 aa precursor; 40-aa leader peptide; 615-aa mature
      protein). Demonstrates that VLCAD deficiency impairs long-chain (palmitate) beta-oxidation and
      that restoring ~20% VLCAD activity restores palmitate beta-oxidation flux.
    supporting_text: >-
      raising VLCAD activity to approximately 20% of normal control fibroblast activity raised
      palmitic acid beta-oxidation flux to the level found in control fibroblasts
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: >-
      PubMed-verified foundational VLCAD paper supporting its long-chain acyl-CoA dehydrogenase
      activity and FAO role.
- id: PMID:8466512
  title: A novel disease with deficiency of mitochondrial very-long-chain acyl-CoA
    dehydrogenase.
  findings:
  - statement: >-
      First identification of VLCAD deficiency as a distinct disease, based on very low
      palmitoyl-CoA (C16) dehydrogenase activity and loss of anti-VLCAD immunoreactivity in patients.
    supporting_text: >-
      found to have a novel disease, VLCAD deficiency, as judged from the results of very low
      palmitoyl-CoA dehydrogenase activity and the lack of immunoreactivity toward antibody raised
      to purified VLCAD
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: >-
      PubMed-verified. Supports VLCAD long-chain acyl-CoA dehydrogenase activity via patient
      deficiency.
- id: PMID:9461620
  title: Catalytic and FAD-binding residues of mitochondrial very long chain acyl-coenzyme
    A dehydrogenase.
  findings:
  - statement: >-
      VLCAD is one of four flavoproteins catalyzing the initial step of mitochondrial beta-oxidation.
      Glu-422 is the catalytic base (E422Q abolishes activity by preventing the VLCAD-palmitoyl-CoA
      charge-transfer complex); Phe-418 is required for FAD binding/reduction and FAD loss
      destabilizes folding.
    supporting_text: >-
      Glu-422 of VLCAD has been presumed to be the catalytic residue that abstracts the alpha-proton
      in the alphabeta-dehydrogenation reaction. Replacing Glu-422 with glutamine (E422Q) caused a
      loss of enzyme activity
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: >-
      PubMed-verified. Direct mechanistic evidence for VLCAD catalytic activity and FAD binding.
- id: PMID:9599005
  title: Very-long-chain acyl-CoA dehydrogenase subunit assembles to the dimer form
    on mitochondrial inner membrane.
  findings:
  - statement: >-
      Mature VLCAD is a homodimer of ~70 kDa subunits associated with the mitochondrial inner
      membrane; membrane association precedes and is required for dimer assembly. The monomeric
      mutant S583W fails to bind the membrane and remains soluble in the matrix.
    supporting_text: >-
      association of VLCAD protein with mitochondrial inner membrane is necessary for dimer assembly
      and formation of mature VLCAD
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: >-
      PubMed-verified. Establishes VLCAD homodimerization and inner-membrane localization.
- id: Reactome:R-HSA-1791069
  title: Expression of ACADVL
  findings: []
- id: Reactome:R-HSA-77299
  title: palmitoyl-CoA+FAD => trans-Hexadec-2-enoyl-CoA+FADH2
  findings:
  - statement: >-
      Reactome reaction for the VLCAD-catalyzed dehydrogenation of palmitoyl-CoA, placed in the
      mitochondrial matrix compartment.