ILV1 encodes the biosynthetic threonine dehydratase (threonine deaminase, EC 4.3.1.19) of Saccharomyces cerevisiae, a pyridoxal-phosphate-dependent homotetrameric enzyme of the serine/threonine dehydratase family with two C-terminal ACT-like regulatory domains. Imported into mitochondria, Ilv1 deaminates L-threonine to 2-oxobutanoate and ammonia, the first and committed step of L-isoleucine synthesis; 2-oxobutanoate is then condensed with pyruvate by acetohydroxyacid synthase (Ilv2/Ilv6). Ilv1 is feedback-inhibited by isoleucine and activated by valine, and ilv1 mutants require isoleucine. ILV1 expression is under general amino acid control. It is distinct from the catabolic, non-allosteric serine/threonine deaminase Cha1, although the two enzymes can partially substitute for one another.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004794 threonine deaminase activity | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA from the threonine-deaminase node PTN002459384 (seeded by E. coli IlvA among others). Ilv1 is the biosynthetic, isoleucine-feedback-inhibited threonine dehydratase (EC 4.3.1.19); correct and core. Supporting Evidence: file:yeast/ILV1/ILV1-uniprot.txt Reaction=L-threonine = 2-oxobutanoate + NH4(+) PMID:7042346 Whereas the anabolic enzyme is an allosteric enzyme sensitive to feedback inhibition by isoleucine |
| GO:0004794 threonine deaminase activity | IEA GO_REF:0000120 | ACCEPT | Summary: Combined IEA (ARBA, InterPro IPR005787 biosynthetic threonine dehydratase, RHEA:22108, EC 4.3.1.19); correct. Supporting Evidence: file:yeast/ILV1/ILV1-uniprot.txt Reaction=L-threonine = 2-oxobutanoate + NH4(+) |
| GO:0004794 threonine deaminase activity | IMP PMID:5345980 Regulation of isoleucine-valine biosynthesis in Saccharomyce... | ACCEPT | Summary: Brunner et al. 1969 characterized an altered threonine deaminase in an is-1 (ilv1) mutant. Only the title is cached; the enzyme/locus identity is classical and agrees with UniProt, so defer to the curator. Supporting Evidence: PMID:5345980 Altered threonine deaminase in an is-1 mutant responding to threonine file:yeast/ILV1/ILV1-uniprot.txt Reaction=L-threonine = 2-oxobutanoate + NH4(+) |
| GO:0004794 threonine deaminase activity | RCA GO_REF:0000123 | ACCEPT | Summary: RCA from YeastPathways BRANCHED-CHAIN-AA-SYN-PWY-1 (superpathway of branched chain amino acid biosynthesis). Ilv1 catalyses the first, committed step of isoleucine synthesis (L-threonine -> 2-oxobutanoate + NH4+); MF correct. Supporting Evidence: file:yeast/ILV1/ILV1-uniprot.txt Reaction=L-threonine = 2-oxobutanoate + NH4(+) |
| GO:0004794 threonine deaminase activity | RCA GO_REF:0000123 | ACCEPT | Summary: RCA from YeastPathways ILEUSYN-PWY-1 (L-isoleucine biosynthesis I (from threonine)). Ilv1 catalyses the threonine deamination step of this pathway; MF correct. Supporting Evidence: file:yeast/ILV1/ILV1-uniprot.txt Reaction=L-threonine = 2-oxobutanoate + NH4(+) |
| GO:0005739 mitochondrion | HDA PMID:14562095 Global analysis of protein localization in budding yeast. | ACCEPT | Summary: Ilv1 detected in the genome-wide GFP-fusion localization survey; consistent with its N-terminal targeting and low-throughput data. Supporting Evidence: PMID:14562095 We classify these proteins, representing 75% of the yeast proteome, into 22 distinct subcellular localization categories file:yeast/ILV1/ILV1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion |
| GO:0005739 mitochondrion | HDA PMID:14576278 The proteome of Saccharomyces cerevisiae mitochondria. | ACCEPT | Summary: Ilv1 detected in the mass-spectrometric proteome of highly purified mitochondria (Sickmann et al.); consistent with its N-terminal targeting and low-throughput data. Supporting Evidence: PMID:14576278 The proteins of highly pure yeast mitochondria were separated by several independent methods and analyzed by tandem MS file:yeast/ILV1/ILV1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion |
| GO:0005739 mitochondrion | HDA PMID:16823961 Toward the complete yeast mitochondrial proteome: multidimen... | ACCEPT | Summary: Ilv1 detected in the PROMITO multidimensional mitochondrial proteome; consistent with its N-terminal targeting and low-throughput data. Supporting Evidence: PMID:16823961 A total of 851 different proteins (PROMITO dataset) were identified file:yeast/ILV1/ILV1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion |
| GO:0005739 mitochondrion | HDA PMID:24769239 Quantitative variations of the mitochondrial proteome and ph... | ACCEPT | Summary: Ilv1 detected in the quantitative proteome of isolated mitochondria under fermentative/respiratory growth; consistent with its N-terminal targeting and low-throughput data. Supporting Evidence: PMID:24769239 we performed an overall quantitative proteomic and phosphoproteomic study of isolated mitochondria file:yeast/ILV1/ILV1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion |
| GO:0005739 mitochondrion | IEA GO_REF:0000044 | ACCEPT | Summary: UniProt subcellular location 'Mitochondrion' (based on the GFP and proteomics data) mapped to GO; correct. Supporting Evidence: file:yeast/ILV1/ILV1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion |
| GO:0005829 cytosol | RCA GO_REF:0000123 | REMOVE | Summary: is_active_in cytosol from YeastPathways BRANCHED-CHAIN-AA-SYN-PWY-1 (superpathway of branched chain amino acid biosynthesis). YeastPathways defaults its reactions to the cytosol; for Ilv1 this contradicts the experimental location. Ilv1 is a presequence-bearing mitochondrial precursor found in mitochondria by GFP imaging and in several purified-mitochondria proteomes. Supporting Evidence: file:yeast/ILV1/ILV1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion PMID:14576278 The proteins of highly pure yeast mitochondria were separated by several independent methods and analyzed by tandem MS |
| GO:0005829 cytosol | RCA GO_REF:0000123 | REMOVE | Summary: is_active_in cytosol from YeastPathways ILEUSYN-PWY-1 (L-isoleucine biosynthesis I (from threonine)). YeastPathways defaults its reactions to the cytosol; for Ilv1 this contradicts the experimental location. The isoleucine branch (Ilv1 through Ilv3 and Bat1) operates in the mitochondrial matrix. Supporting Evidence: file:yeast/ILV1/ILV1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion PMID:14576278 The proteins of highly pure yeast mitochondria were separated by several independent methods and analyzed by tandem MS |
| GO:0006520 amino acid metabolic process | IEA GO_REF:0000002 | MODIFY | Summary: InterPro mapping from the PLP-dependent Ser/Thr dehydratase domain (IPR000634) to generic 'amino acid metabolic process'. Correct but uninformative; the established process is isoleucine biosynthesis. Proposed replacements: L-isoleucine biosynthetic process Supporting Evidence: PMID:7042346 Whereas the anabolic enzyme is an allosteric enzyme sensitive to feedback inhibition by isoleucine |
| GO:0006567 L-threonine catabolic process | IGI PMID:7042346 Occurrence of a catabolic L-serine (L-threonine) deaminase i... | KEEP AS NON CORE | Summary: Ramos & Wiame found ilv1 mutants still grow on threonine/serine as sole nitrogen source and that cha1 mutation in an ilv1 background abolishes threonine utilisation; the two deaminases show limited mutual compensation. The IGI with CHA1 therefore records a genuine but minor, back-up contribution of Ilv1 to threonine catabolism; the catabolic enzyme is Cha1. Supporting Evidence: PMID:7042346 Saccharomyces cerevisiae mutants lacking the anabolic L-threonine deaminase, the ilv1- mutants, have been found to exhibit a normal ability to grow, without auxotrophy towards isoleucine, on L-threonine of L-serine as only nitrogen nutrient PMID:7042346 display a limited ability to compensate for one another's absence and appear to play clearly distinct roles under normal physiological conditions |
| GO:0009082 branched-chain amino acid biosynthetic process | RCA GO_REF:0000123 | ACCEPT | Summary: RCA from YeastPathways BRANCHED-CHAIN-AA-SYN-PWY-1 (superpathway of branched chain amino acid biosynthesis). Ilv1 supplies 2-oxobutanoate for isoleucine, one of the three branched-chain amino acids; correct (isoleucine-specific child GO:1901705 is also present). Supporting Evidence: file:yeast/ILV1/ILV1-uniprot.txt Reaction=L-threonine = 2-oxobutanoate + NH4(+) |
| GO:0030170 pyridoxal phosphate binding | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro mapping (IPR000634, PLP-binding site). Ilv1 is a fold-type II PLP enzyme and UniProt lists PLP as cofactor; correct cofactor-binding annotation. Supporting Evidence: file:yeast/ILV1/ILV1-uniprot.txt Name=pyridoxal 5'-phosphate; Xref=ChEBI:CHEBI:597326; |
| GO:1901705 L-isoleucine biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA from PTN002463966 (biosynthetic threonine deaminases); correct for Ilv1. Supporting Evidence: PMID:7042346 Whereas the anabolic enzyme is an allosteric enzyme sensitive to feedback inhibition by isoleucine |
| GO:1901705 L-isoleucine biosynthetic process | IEA GO_REF:0000120 | ACCEPT | Summary: Combined IEA (ARBA, IPR005787); correct. Supporting Evidence: file:yeast/ILV1/ILV1-uniprot.txt Reaction=L-threonine = 2-oxobutanoate + NH4(+) |
| GO:1901705 L-isoleucine biosynthetic process | IMP PMID:5345980 Regulation of isoleucine-valine biosynthesis in Saccharomyce... | ACCEPT | Summary: Classical ilv1 (is-1) mutant with altered threonine deaminase; ilv1 mutants are isoleucine auxotrophs. Title only cached; defer to curator, consistent with UniProt pathway assignment. Supporting Evidence: PMID:5345980 Altered threonine deaminase in an is-1 mutant responding to threonine PMID:7042346 Whereas the anabolic enzyme is an allosteric enzyme sensitive to feedback inhibition by isoleucine |
| GO:1901705 L-isoleucine biosynthetic process | RCA GO_REF:0000123 | ACCEPT | Summary: RCA from YeastPathways ILEUSYN-PWY-1 (L-isoleucine biosynthesis I (from threonine)). Ilv1 catalyses step 1 (2-oxobutanoate from L-threonine) of isoleucine synthesis; core BP. Supporting Evidence: file:yeast/ILV1/ILV1-uniprot.txt Reaction=L-threonine = 2-oxobutanoate + NH4(+) |
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Download this section (compressed HTML)Threonine deaminase, catalyzes first step in isoleucine biosynthesis; expression is under general amino acid control; ILV1 locus exhibits highly positioned nucleosomes whose organization is independent of known ILV1 regulation
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