Cysteine lyase
In enzymology, a cysteine lyase () 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 metabolism. It employs one cofactor , pyridoxal phosphate. Evolution. Genes encoding cysteine lyase (CL) originated around 300 million years ago by a tandem gene duplication and neofunctionalization of cystathionine beta-lyase (CBS) shortly after the split of mammalian and reptilian lineages. CL genes are found only in Sauropsida where are involved in a metabolic pathway for sulfur metabolism in the chicken egg.