Valine biosynthesis (WP2)

Saccharomyces cerevisiae

Biosynthesis of the aromatic amino acids tyrosine, phenylalanine, and tryptophan proceeds via a common pathway to chorismate, at which point the pathway branches(CITS:[Jones][1943992]). One branch proceeds to tyrosine and phenylalanine, and the other to tryptophan (CITS:[Jones]). The series of reactions to chorismate, called the shikimate pathway, and the series of reactions from chorismate to tryptophan have been found to be common to all eukaryotes and prokaryotes studied thus far (as reported in (CITS:[1943992])). In contrast, there appear to be two separate routes for tyrosine and phenylalanine biosynthesis from chorismate, only one of which has been found in S. cerevisiae (CITS:[1943992]). S. cerevisiae, similar to E. coli, synthesize tyrosine and phenylalanine via the intermediate 4-hydroxyphenylpyruvate and phenylpyruvate, respectively, whereas some other organisms synthesize them via arogenate (CITS:[1943992]). Aromatic amino acid biosynthesis in S. cerevisiae is controlled by a combination of feedback inhibition, activation of enzyme activity, and regulation of enzyme synthesis (CITS:[Jones][1943992]). The carbon flow through the pathways is regulated primarily at the initial step and the branching points by the terminal end-products. The initial step of chorismate biosynthesis can be catalyzed by two isoenzymes Aro3p or Aro4p, whereby Aro3p is inhibited by phenylalanine, and Aro4p by tyrosine (CITS:[Jones][1943992]). The first step in the phenylalanine-tyrosine branch is feedback inhibited by tyrosine and activated by tryptophan, and the first step in the tryptophan branch is feedback inhibited by tryptophan (CITS:[1943992]). The transcriptional activator GCN4 regulates most of the genes encoding for the aromatic amino acid biosynthetic enzymes; however, no GCN4 regulation was found for TYR1 of the tyrosine branch, ARO7 of the tyrosine and phenylalanine branch, or TRP1 of the tryptophan branch, (CITS:[1943992]). SOURCE: SGD pathways,


Meredith Braymer , Egon Willighagen , Daniela Digles , Eric Weitz , and Martina Summer-Kutmon


last edited

Discuss this pathway

Check for ongoing discussions or start your own.

Cited In

Are you planning to include this pathway in your next publication? See How to Cite and add a link here to your paper once it's online.


Saccharomyces cerevisiae



Pathway Ontology

valine biosynthetic pathway


Label Type Compact URI Comment
NADPH Metabolite cas:53-57-6
2 pyruvate Metabolite chebi:15361
2,3-dihydroxy-isovalerate Metabolite chebi:49072
NADP Metabolite hmdb:HMDB0000217
2-keto-isovalerate Metabolite chebi:11851
CO2 Metabolite chebi:16526
2-aceto-lactate Metabolite pubchem.compound:13999770
L-glutamate Metabolite cas:56-86-0
H2O Metabolite chebi:15377
H+ Metabolite chebi:15378
2-oxoglutarate Metabolite chebi:16810
L-valine Metabolite chebi:16414
ILV6 GeneProduct sgd:S000000515
ILV2 GeneProduct sgd:S000004714
ILV3 GeneProduct sgd:S000003777
BAT1 GeneProduct sgd:S000001251
BAT2 GeneProduct sgd:S000003909


  1. Regulation of isoleucine-valine biosynthesis in Saccharomyces cerevisiae. Holmberg S, Petersen JG. Curr Genet. 1988 Mar;13(3):207–17. PubMed Europe PMC Scholia