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