EC - Tryptophanase

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IntEnz Enzyme Nomenclature


Accepted name:
Other names:
L-tryptophan indole-lyase
L-tryptophan indole-lyase (deaminating)
Systematic name:
L-tryptophan indole-lyase (deaminating; pyruvate-forming)




A pyridoxal-phosphate protein, requiring K+. The enzyme cleaves a carbon-carbon bond, releasing indole and an unstable enamine product that tautomerizes to an imine form, which undergoes a hydrolytic deamination to form pyruvate and ammonia. The latter reaction, which can occur spontaneously, can also be catalysed by EC, 2-iminobutanoate/2-iminopropanoate deaminase. Also catalyses 2,3-elimination and β-replacement reactions of some indole-substituted tryptophan analogues of L-cysteine, L-serine and other 3-substituted amino acids.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , NIST 74 , UniPathway
Protein domains and families: PROSITE:PDOC00667
Structural data: CSA , EC2PDB
Gene Ontology: GO:0009034
CAS Registry Number: 9024-00-4
UniProtKB/Swiss-Prot: (56) [show] [UniProt]


  1. Burns, R.O. and DeMoss, R.D.
    Properties of tryptophanase from Escherichia coli.
    Biochim. Biophys. Acta 65 : 233-244 (1962). [PMID: 14017164]
  2. Cowell, J.L., Maser, K. and DeMoss, R.D.
    Tryptophanase from Aeromonas liquifaciens. Purification, molecular weight and some chemical, catalytic and immunological properties.
    Biochim. Biophys. Acta 315 : 449-463 (1973).
  3. Newton, W.A., Morino, Y. and Snell, E.E.
    Properties of crystalline tryptophanase.
    J. Biol. Chem. 240 : 1211-1218 (1965). [PMID: 14284727]
  4. Snell, E. E.
    Tryptophanase: structure, catalytic activities, and mechanism of action.
    Adv. Enzymol. Relat. Areas Mol. Biol. 42 : 287-333 (1975). [PMID: 236639]

[EC created 1972]