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)

cysteine-S-conjugate β-lyase
Identifiers
EC no.	4.4.1.13
CAS no.	68652-57-3
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / QuickGO
Search PMC articles PubMed articles NCBI proteins

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 1W7L, 1W7M, and 1W7N.