IUBMB Enzyme Nomenclature


Accepted name: cysteine lyase

Reaction: L-cysteine + sulfite = L-cysteate + hydrogen sulfide

For diagram click here.

Other name(s): cysteine (sulfite) lyase; L-cysteine hydrogen-sulfide-lyase (adding sulfite)

Systematic name: L-cysteine hydrogen-sulfide-lyase (adding sulfite; L-cysteate-forming)

Comments: A pyridoxal-phosphate protein. Can use a second molecule of cysteine (producing lanthionine), or other alkyl thiols, as a replacing agent.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 9079-86-1


1. Tolosa, E.A., Chepurnova, N.K., Khomutov, R.M. and Severin, E.S. Reactions catalysed by cysteine lyase from the yolk sac of chicken embryo. Biochim. Biophys. Acta 171 (1969) 369-371. [PMID: 5813025]

[EC created 1972]

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