Adh4 is an NAD-dependent alcohol dehydrogenase of Schizosaccharomyces pombe belonging to the iron-containing alcohol dehydrogenase family. Mitochondrial fractionation, activity assays and gene disruption place an ethanol-oxidizing activity in the mitochondrial matrix, where it supplies reducing equivalents for respiration. Adh4 also supports compensatory ethanol production in adh1-null cells, although the compartment of that reductive activity is unresolved. The family name does not establish its physiological metal: UniProt assigns zinc by similarity, and direct native metal identification remains lacking.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004022 alcohol dehydrogenase (NAD+) activity | EXP PMID:15040954 A distinct type of alcohol dehydrogenase, adh4+, complements... | MODIFY | Summary: NAD-dependent ADH activity is supported in both mitochondrial ethanol oxidation and compensatory ethanol production. Reason: The assayed substrate and established physiological reaction support the more specific ethanol dehydrogenase activity already annotated here. Proposed replacements: ethanol dehydrogenase (NAD+) activity Supporting Evidence: PMID:16999687 we show conclusively that the novel mitochondrial ADH is encoded by adh4 file:SCHPO/adh4/adh4-uniprot.txt Reaction=ethanol + NAD(+) = acetaldehyde + NADH + H(+); |
| GO:0004022 alcohol dehydrogenase (NAD+) activity | EXP PMID:16999687 Identification of a mitochondrial alcohol dehydrogenase in S... | MODIFY | Summary: NAD-dependent ADH activity is supported in both mitochondrial ethanol oxidation and compensatory ethanol production. Reason: The assayed substrate and established physiological reaction support the more specific ethanol dehydrogenase activity already annotated here. Proposed replacements: ethanol dehydrogenase (NAD+) activity Supporting Evidence: PMID:16999687 we show conclusively that the novel mitochondrial ADH is encoded by adh4 file:SCHPO/adh4/adh4-uniprot.txt Reaction=ethanol + NAD(+) = acetaldehyde + NADH + H(+); |
| GO:0004022 alcohol dehydrogenase (NAD+) activity | IBA GO_REF:0000033 | MODIFY | Summary: NAD-dependent ADH activity is supported in both mitochondrial ethanol oxidation and compensatory ethanol production. Reason: The assayed substrate and established physiological reaction support the more specific ethanol dehydrogenase activity already annotated here. Propagation Review Root cause: TERM SCOPING PROBLEM Failure modes: GRANULARITY MISMATCH Sources checked: PANTHER:PTN002608572 SUPPORTS TRANSFER The inherited claim is consistent with the target-specific evidence and family placement. Proposed replacements: ethanol dehydrogenase (NAD+) activity Supporting Evidence: PMID:16999687 we show conclusively that the novel mitochondrial ADH is encoded by adh4 file:SCHPO/adh4/adh4-uniprot.txt Reaction=ethanol + NAD(+) = acetaldehyde + NADH + H(+); |
| GO:0004022 alcohol dehydrogenase (NAD+) activity | IEA GO_REF:0000120 | MODIFY | Summary: NAD-dependent ADH activity is supported in both mitochondrial ethanol oxidation and compensatory ethanol production. Reason: The assayed substrate and established physiological reaction support the more specific ethanol dehydrogenase activity already annotated here. Proposed replacements: ethanol dehydrogenase (NAD+) activity Supporting Evidence: PMID:16999687 we show conclusively that the novel mitochondrial ADH is encoded by adh4 file:SCHPO/adh4/adh4-uniprot.txt Reaction=ethanol + NAD(+) = acetaldehyde + NADH + H(+); |
| GO:0005739 mitochondrion | EXP PMID:16999687 Identification of a mitochondrial alcohol dehydrogenase in S... | ACCEPT | Summary: Adh4-dependent ethanol oxidation is experimentally localized to mitochondria; the separate matrix assignment supplies finer resolution. Reason: PMID:16999687 reports ethanol-dependent, antimycin-sensitive oxygen uptake and alcohol dehydrogenase activity in isolated S. pombe mitochondria. The adh4 knockout identifies the gene responsible; detergent latency separately supports a matrix enzyme. Mitochondrion is an informative, directly supported organelle assertion and is retained under the root-organelle policy rather than replaced by matrix. The two existing matrix annotations remain separate. These oxidative assays do not establish the compartment of compensatory reductive fermentation. Supporting Evidence: PMID:16999687 we show conclusively that the novel mitochondrial ADH is encoded by adh4 PMID:16999687 which demonstrates that the enzyme is located in the matrix |
| GO:0005739 mitochondrion | HDA PMID:16823372 ORFeome cloning and global analysis of protein localization ... | ACCEPT | Summary: The curated YFP-screen mitochondrial assignment is retained with independent target biochemical corroboration. Reason: PMID:16823372 is an ORFeome YFP localization screen, not the isolated-mitochondrial enzyme assay. Its cached abstract describes the screen but does not display the adh4 image or identify its submitochondrial topology. Retain the curator-supported mitochondrial observation because independent target evidence in PMID:16999687 directly establishes Adh4-dependent mitochondrial ethanol oxidation. The screen is not credited with detergent latency, gene-disruption identity or matrix resolution; those derive from the separate biochemical study. An informative root-organelle assertion remains valid alongside the two supported matrix rows. Supporting Evidence: PMID:16823372 we determined the localization of 4,431 proteins PMID:16999687 we show conclusively that the novel mitochondrial ADH is encoded by adh4 |
| GO:0005759 mitochondrial matrix | EXP PMID:16999687 Identification of a mitochondrial alcohol dehydrogenase in S... | ACCEPT | Summary: Detergent-latency of ADH activity in isolated mitochondria (about 16-fold increase with Triton X-100) places the adh4 enzyme in the matrix. Reason: Direct experimental evidence for the specific sub-mitochondrial compartment. Supporting Evidence: PMID:16999687 which demonstrates that the enzyme is located in the matrix |
| GO:0005759 mitochondrial matrix | IEA GO_REF:0000044 | ACCEPT | Summary: UniProt subcellular-location mapping (SL-0170 Mitochondrion matrix), which in this entry rests on the experimental data of Crichton et al. 2007. Reason: Correct, experimentally supported location. Supporting Evidence: file:SCHPO/adh4/adh4-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion matrix PMID:16999687 which demonstrates that the enzyme is located in the matrix |
| GO:0016491 oxidoreductase activity | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO from the Fe-ADH/GldA family (IPR001670, IPR018211) gives the root oxidoreductase activity. Reason: Too general; the specific activity is experimentally established. Proposed replacements: ethanol dehydrogenase (NAD+) activity Supporting Evidence: file:SCHPO/adh4/adh4-uniprot.txt Reaction=ethanol + NAD(+) = acetaldehyde + NADH + H(+); |
| GO:0019655 pyruvate fermentation to ethanol | IGI PMID:15040954 A distinct type of alcohol dehydrogenase, adh4+, complements... | ACCEPT | Summary: Adh4 expression rises in adh1-null cells and sustains ethanol production; disruption of both genes produces the nonfermentative phenotype. The compartment of this compensatory reductive activity was not established by the separate mitochondrial oxidation study. Reason: Genetic evidence supports direct catalysis of the acetaldehyde-to-ethanol step. The two-enzyme sufficiency conclusion is limited to the strains and growth conditions tested in PMID:15040954. Supporting Evidence: PMID:15040954 only these two ADHs produce ethanol for fermentative growth PMID:15040954 ADH4-like gene product (SPAC5H10.06C named adh4(+)) |
| GO:0046395 carboxylic acid catabolic process | IEA GO_REF:0000117 | MODIFY | Summary: Adh4 contributes the final reductive reaction of pyruvate fermentation to ethanol in adh1-deficient cells. Reason: Carboxylic acid catabolism is a true ancestor of pyruvate fermentation to ethanol: a participating enzyme need not directly consume the initial carboxylic acid. Refine to the independently supported fermentation process rather than reject this electronic annotation on substrate-name grounds. Proposed replacements: pyruvate fermentation to ethanol Supporting Evidence: PMID:15040954 only these two ADHs produce ethanol for fermentative growth |
| GO:0046872 metal ion binding | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro2GO from the Fe-ADH family gives metal ion binding. Group III ADHs bind a divalent metal (Fe2+ or Zn2+) in the active site; UniProt records Zn2+ by similarity for adh4. Reason: Correct at this level; the specific metal in vivo is not established, so the generic term is appropriate. Supporting Evidence: file:SCHPO/adh4/adh4-uniprot.txt Name=Zn(2+); Xref=ChEBI:CHEBI:29105; Evidence={ECO:0000250}; file:SCHPO/adh4/adh4-uniprot.txt Belongs to the iron-containing alcohol dehydrogenase |
| GO:0120542 ethanol dehydrogenase (NAD+) activity | IDA PMID:16999687 Identification of a mitochondrial alcohol dehydrogenase in S... | ACCEPT | Summary: Crichton et al. 2007 showed ethanol-dependent, trifluoroethanol-sensitive ADH activity and respiration in isolated mitochondria, abolished by adh4 deletion. This is direct evidence that adh4 oxidises ethanol with NAD+. Reason: Direct assay of the specific activity attributable to adh4. Supporting Evidence: PMID:16999687 exhibit antimycin A-sensitive oxygen uptake activity that is exclusively dependent on ethanol PMID:16999687 we show conclusively that the novel mitochondrial ADH is encoded by adh4 |
| GO:0120542 ethanol dehydrogenase (NAD+) activity | IEA GO_REF:0000120 | ACCEPT | Summary: Combined IEA (ARBA, RHEA:25290) for ethanol dehydrogenase (NAD+) activity. Matches the experimental evidence. Reason: Correct specific activity. Supporting Evidence: file:SCHPO/adh4/adh4-uniprot.txt Reaction=ethanol + NAD(+) = acetaldehyde + NADH + H(+); |
| GO:0120542 ethanol dehydrogenase (NAD+) activity | IMP PMID:15040954 A distinct type of alcohol dehydrogenase, adh4+, complements... | ACCEPT | Summary: Sakurai et al. 2004: ethanol production in adh1 null cells depends on adh4, so adh4 can reduce acetaldehyde to ethanol in vivo. The curator had the full text; the abstract is consistent. Reason: Genetic evidence for the activity in the reductive direction, consistent with biochemical data. Supporting Evidence: PMID:15040954 ADH4-like gene product (SPAC5H10.06C named adh4(+)) PMID:15040954 only these two ADHs produce ethanol for fermentative growth |
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Download this section (compressed HTML)Q: Should adh4 carry an ethanol catabolic process (GO:0006068) annotation for its mitochondrial ethanol oxidation, given that S. pombe cannot use ethanol as sole carbon source?
Q: Where does adh4 act during compensatory fermentation in adh1 null cells: is a cytosolic pool produced, or is acetaldehyde reduced in the matrix with NADH exchanged by a shuttle?
Q: Is adh4 a zinc- or an iron-activated enzyme in vivo, and is its induction by zinc deficiency a metal-sparing replacement for the zinc enzyme adh1?
Experiment: Localise endogenously tagged adh4 in wild-type and adh1 null cells under fermentative conditions to test whether the protein relocates to the cytosol when it supports fermentation.
Experiment: Determine metal content and metal-dependent activity of purified adh4 (Fe2+ vs Zn2+) by ICP-MS and reconstitution.
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