Cysteine-S-conjugate beta-lyase

The enzyme cysteine-S-conjugate β-lyase (EC 4.4.1.13) catalyzes the chemical reaction


 * an L -cysteine-S-conjugate + H2O = a thiol + NH3 + pyruvate (overall reaction)
 * (1a) an L -cysteine-S-conjugate = a thiol + 2-aminoprop-2-enoate
 * (1b) 2-aminoprop-2-enoate = 2-iminopropanoate (spontaneous)
 * (1c) 2-iminopropanoate + H2O = pyruvate + NH3 (spontaneous)

This enzyme belongs to the family of lyases, specifically the class of carbon-sulfur lyases. The systematic name of this enzyme class is  L -cysteine-S-conjugate thiol-lyase (deaminating; pyruvate-forming). Other names in common use include cysteine conjugate β-lyase, glutamine transaminase K/cysteine conjugate β-lyase, and  L -cysteine-S-conjugate thiol-lyase (deaminating). It employs one cofactor, pyridoxal phosphate.

Structural studies
As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes, , and.