Isoleucine degradation (Saccharomyces cerevisiae)
From WikiPathways
Description
While Saccharomyces cerevisiae can use most amino acids as their sole nitrogen source, they can only use a few amino acids as a carbon source to support growth. This is in contrast to most eukaryotes and some fungi, which can metabolize amino acids completely, utilizing them as sole sources of carbon and nitrogen. S. cerevisiae degrade the branched-chain amino acids (iso-leucine, leucine, and valine) and the aromatic amino acids (tryptophan, phenylalanine, and tyrosine) via the Ehrlich pathway. This pathway is comprised of the following steps: 1) deamination of the amino acid to the corresponding alpha-keto acid; 2) decarboxylation of the resulting alpha-keto acid to the respective aldehyde; and, 3) reduction of the aldehyde to form the corresponding long chain or complex alcohol, known as a fusel alcohol or fusel oil. Fusel alcohols are important flavor and aroma compounds in yeast-fermented food products and beverages Each of the three steps in branched-chain amino acid degradation can be catalyzed by more than one isozyme; which enzyme is used appears to depend on the amino acid, the carbon source and the stage of growth of the culture. The initial transamination step in iso-leucine degradation can be catalyzed by either of the branched-chain amino acid transaminases BAT1 (mitochondrial) or BAT2 (cytosolic). The subsequent decarboxylation step can be catalyzed by any one of the five decarboxylases (Pdc1p, Pdc5p, Pdc6p, Thi3p, and Aro10p) and the final step can be catalyzed by any one of six alcohol dehydrogenases (Adh1p, Adh2p, Adh3p, Adh4p, Adh5p, and Sfa1p).
SOURCE: SGD pathways, http://pathway.yeastgenome.org/server.html
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Ontology Terms
Bibliography
- Prohl C, Kispal G, Lill R; ''Branched-chain-amino-acid transaminases of yeast Saccharomyces cerevisiae.''; Methods Enzymol, 2000 PubMed Europe PMC Scholia
- Kispal G, Steiner H, Court DA, Rolinski B, Lill R; ''Mitochondrial and cytosolic branched-chain amino acid transaminases from yeast, homologs of the myc oncogene-regulated Eca39 protein.''; J Biol Chem, 1996 PubMed Europe PMC Scholia
- Eden A, Simchen G, Benvenisty N; ''Two yeast homologs of ECA39, a target for c-Myc regulation, code for cytosolic and mitochondrial branched-chain amino acid aminotransferases.''; J Biol Chem, 1996 PubMed Europe PMC Scholia
- Dickinson JR, Harrison SJ, Dickinson JA, Hewlins MJ; ''An investigation of the metabolism of isoleucine to active Amyl alcohol in Saccharomyces cerevisiae.''; J Biol Chem, 2000 PubMed Europe PMC Scholia
- ''isoleucine degradation''; Yeast Pathways,
History
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External references
DataNodes
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Name | Type | Database reference | Comment |
---|---|---|---|
(S)-3-methyl-2-oxopentanoate | Metabolite | 35146 (ChEBI) | |
2-methylbutanal | Metabolite | 16182 (ChEBI) | |
2-methylbutanol | Metabolite | 48945 (ChEBI) | |
2-oxoglutarate | Metabolite | 16810 (ChEBI) | |
ADH4 | GeneProduct | YGL256W (Ensembl) | |
ADH5 | GeneProduct | YBR145W (Ensembl) | |
ARO10 | GeneProduct | S000002788 (SGD) | |
BAT1 | GeneProduct | S000001251 (SGD) | |
BAT2 | GeneProduct | S000003909 (SGD) | |
CO2 | Metabolite | 16526 (ChEBI) | |
H+ | Metabolite | 15378 (ChEBI) | |
L-glutamate | Metabolite | 56-86-0 (CAS) | |
L-isoleucine | Metabolite | 58045 (ChEBI) | |
NAD+ | Metabolite | 57540 (ChEBI) | |
NADH | Metabolite | 57945 (ChEBI) | |
PDC1 | GeneProduct | S000004034 (SGD) | |
PDC5 | GeneProduct | S000004124 (SGD) | |
PDC6 | GeneProduct | S000003319 (SGD) | |
SFA1 | GeneProduct | YDL168W (Ensembl) | |
THI3 | GeneProduct | S000002238 (SGD) |
Annotated Interactions
No annotated interactions