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Pathway: leucine degradation

Biochemical pathways in S. cerevisiae are manually curated and maintained in the YeastPathways database. This page summarizes the genes, enzymes, and metabolites involved in the pathway, along with the curated literature.

Pathway Name
leucine degradation
Pathway ID
PWY3O-4112
SGD ID
SGD:S000203392
Genes
ADH1 | ADH2 | ADH3 | ADH4 | ADH5 | ARO10 | BAT1 | BAT2 | SFA1 | THI3
Aliases
Ehrlich pathway
Chemical Compounds
2-oxoglutarate(2-) | 3-methylbutanal | 4-methyl-2-oxopentanoate | L-glutamate(1-) | L-leucine zwitterion | NAD(1-) | NADH(2-) | carbon dioxide | isoamylol

Pathway Diagram

Diagram of the pathway from YeastPathways. Click "View interactive diagram at YeastPathways" for the zoomable, clickable version.

leucine degradation pathway diagram

View interactive diagram at YeastPathways

Pathway Summary

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 (leucine, iso-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 (as reported in 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 In leucine degradation, Thi3p is believed to be the major decarboxylase

Genes Involved

Genes whose products participate in this pathway, with their systematic names, EC numbers (where the gene product is an enzyme with an assigned EC number), and the gene's SGD description.

GeneSystematic NameEC NumberDescription
ADH1 YOL086C 1.1.1.1, 1.1.1.54, 1.1.1.78 Alcohol dehydrogenase
ADH2 YMR303C 1.1.1.1 Glucose-repressible alcohol dehydrogenase II
ADH3 YMR083W 1.1.1.1 Mitochondrial alcohol dehydrogenase isozyme III
ADH4 YGL256W 1.1.1.1 Alcohol dehydrogenase isoenzyme type IV
ADH5 YBR145W 1.1.1.1 Alcohol dehydrogenase isoenzyme V
ARO10 YDR380W 4.1.1.43, 4.1.1.72, 4.1.1.74, 4.1.1.80 Phenylpyruvate decarboxylase
BAT1 YHR208W 2.6.1.42 Mitochondrial branched-chain amino acid (BCAA) aminotransferase
BAT2 YJR148W 2.6.1.42 Cytosolic branched-chain amino acid (BCAA) aminotransferase
SFA1 YDL168W 1.1.1.1, 1.1.1.284 Bifunctional alcohol dehydrogenase and formaldehyde dehydrogenase
THI3 YDL080C 4.1.1.72 Regulatory protein that binds Pdc2p and Thi2p transcription factors

Functional Networks

Functional Networks show how the genes in this pathway work together: a graph linking the pathway to its genes and their shared GO biological-process terms and phenotype observables, and the GO-CAM causal activity models that involve these genes.

Shared Annotations

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GO-CAMs

GO-CAM (Gene Ontology Causal Activity Model) pathway models that involve the genes in this pathway. A gene can participate in more than one model, so use the dropdown to switch between them; the model for this pathway is shown by default.

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GO Enrichment

Gene Ontology biological-process terms enriched among the genes in this pathway, computed with GO Term Finder. Terms are shown with the number of pathway genes annotated to them and the corrected p-value.

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References

List of references used specifically to curate the information on this page.

Resources

YeastPathways