Tyrosine biosynthesis (WP538)

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 appears 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, http://pathway.yeastgenome.org/server.html


Meredith Braymer , Daniela Digles , Egon Willighagen , Kristina Hanspers , and Eric Weitz


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Saccharomyces cerevisiae



Pathway Ontology

tyrosine biosynthetic pathway


Label Type Compact URI Comment
L-tyrosine Metabolite chebi:17895
NADPH Metabolite cas:53-57-6
NADP Metabolite chebi:44409
chorismate Metabolite chebi:29748
p-hydroxyphenylpyruvate Metabolite chebi:36242
CO2 Metabolite chebi:16526
2-oxoglutarate Metabolite chebi:16810
prephenate Metabolite chebi:29934
L-Glutamate Metabolite chebi:16015
TYR1 GeneProduct sgd:S000000370
ARO9 GeneProduct sgd:S000001179
ARO7 GeneProduct sgd:S000006264
ARO8 GeneProduct sgd:S000003170


  1. Aromatic amino acid biosynthesis in the yeast Saccharomyces cerevisiae: a model system for the regulation of a eukaryotic biosynthetic pathway. Braus GH. Microbiol Rev. 1991 Sep;55(3):349–70. PubMed Europe PMC Scholia
  2. Phenylalanine- and tyrosine-auxotrophic mutants of Saccharomyces cerevisiae impaired in transamination. Urrestarazu A, Vissers S, Iraqui I, Grenson M. Mol Gen Genet. 1998 Jan;257(2):230–7. PubMed Europe PMC Scholia