Biology:Cysteine-S-conjugate beta-lyase

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cysteine-S-conjugate β-lyase
Identifiers
EC number4.4.1.13
CAS number68652-57-3
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO

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 1W7L, 1W7M, and 1W7N.

References

  • "Cysteine conjugate β-lyase in rat liver. A novel enzyme catalyzing formation of thiol-containing metabolites of drugs". J. Biol. Chem. 253 (24): 8854–9. 1978. PMID 721818.