Cysteine lyase

In enzymology, a cysteine lyase (EC 4.4.1.10) is an enzyme that catalyzes the chemical reaction

Thus, the two substrates of this enzyme are L-cysteine and sulfite, whereas its two products are L-cysteate and hydrogen sulfide.

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 hydrogen-sulfide-lyase (adding sulfite L-cysteate-forming). Other names in common use include cysteine (sulfite) lyase, and L-cysteine hydrogen-sulfide-lyase (adding sulfite). This enzyme participates in cysteine metabolism and taurine and hypotaurine metabolism. It employs one cofactor, pyridoxal phosphate.