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In enzymology, a tryptophanase (EC is an enzyme that catalyzes the chemical reaction

L-tryptophan + H2O indole + pyruvate + NH3

Thus, the two substrates of this enzyme are L-tryptophan and H2O, whereas its 3 products are indole, pyruvate, and NH3.

This enzyme belongs to the family of lyases, specifically in the "catch-all" class of carbon-carbon lyases. The systematic name of this enzyme class is L-tryptophan indole-lyase (deaminating; pyruvate-forming). Other names in common use include L-tryptophanase, and L-tryptophan indole-lyase (deaminating). This enzyme participates in tryptophan metabolism and nitrogen metabolism. It has 2 cofactors: pyridoxal phosphate, and Potassium.

Structural studies

As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes 1AX4, 2C44, and 2OQX.


  • IUBMB entry for
  • BRENDA references for (Recommended.)
  • PubMed references for
  • PubMed Central references for
  • Google Scholar references for
  • BURNS RO, DEMOSS RD (1962). "Properties of tryptophanase from Escherichia coli". Biochim. Biophys. Acta. 65: 233&ndash, 44. PMID 14017164.
  • Cowell JL, Maser K and DeMoss, RD (1973). "Tryptophanase from Aeromonas liquifaciens. Purification, molecular weight and some chemical, catalytic and immunological properties". Biochim. Biophys. Acta. 315: 449&ndash, 463.
  • NEWTON WA, MORINO Y, SNELL EE (1965). "PROPERTIES OF CRYSTALLINE TRYPTOPHANASE". J. Biol. Chem. 240: 1211&ndash, 8. PMID 14284727.

External links

The CAS registry number for this enzyme class is 9024-00-4.

Gene Ontology (GO) codes