EC - Tryptophan synthase

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IntEnz Enzyme Nomenclature


Accepted name:
tryptophan synthase
Other names:
L-tryptophan synthetase
indoleglycerol phosphate aldolase
tryptophan desmolase
tryptophan synthetase
L-serine hydro-lyase (adding indoleglycerol-phosphate)
Systematic name:
L-serine hydro-lyase [adding 1-C-(indol-3-yl)glycerol 3-phosphate; L-tryptophan and glyceraldehyde-3-phosphate-forming]




A pyridoxal-phosphate protein. The α-subunit catalyses the conversion of 1-C-(indol-3-yl)glycerol 3-phosphate to indole and D-glyceraldehyde 3-phosphate (this reaction was listed formerly as EC The indole migrates to the β-subunit where, in the presence of pyridoxal 5'-phosphate, it is combined with L-serine to form L-tryptophan. In some organisms this enzyme is part of a multifunctional protein that also includes one or more of the enzymes EC (anthranilate phosphoribosyltransferase), EC (indole-3-glycerol-phosphate synthase), EC (anthranilate synthase) and EC (phosphoribosylanthranilate isomerase). In thermophilic organisms, where the high temperature enhances diffusion and causes the loss of indole, a protein similar to the β subunit can be found (EC That enzyme cannot combine with the α unit of EC to form a complex.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC00151 , PROSITE:PDOC00152
Structural data: CSA , EC2PDB
Gene Ontology: GO:0004834
CAS Registry Number: 9014-52-2
UniProtKB/Swiss-Prot: (1000) [show] [UniProt]


  1. Crawford, I.P. and Yanofsky, C.
    On the separation of the tryptophan synthetase of Escherichia coli into two protein components.
    Proc. Natl. Acad. Sci. USA 44 : 1161-1170 (1958). [PMID: 16590328]
  2. Creighton, T.E. and Yanofsky, C.
    Chorismate to tryptophan (Escherichia coli) - anthranilate synthetase, PR transferase, PRA isomerase, InGP synthetase, tryptophan synthetase.
    Methods Enzymol. 17A : 365-380 (1970).
  3. Hütter, R., Niederberger, P. and DeMoss, J.A.
    Tryptophan biosynthetic genes in eukaryotic microorganisms.
    Annu. Rev. Microbiol. 40 : 55-77 (1986). [PMID: 16526091]
  4. Hyde, C.C., Ahmed, S.A., Padlan, E.A., Miles, E.W. and Davies, D.R.
    Three-dimensional structure of the tryptophan synthase α2β2 multienzyme complex from Salmonella typhimurium.
    J. Biol. Chem. 263 : 17857-17871 (1988). [PMID: 3053720]
  5. Woehl, E. and Dunn, M.F.
    Mechanisms of monovalent cation action in enzyme catalysis: the tryptophan synthase α-, β-, and αβ-reactions.
    Biochemistry 38 : 7131-7141 (1999). [PMID: 10353823]

[EC created 1961, modified 1976, modified 2002, modified 2011]