Cysteine lyase
In enzymology, a cysteine lyase (EC 4.4.1.10) [1] is an enzyme that catalyzes the chemical reaction
- L-cysteine + sulfite L-cysteate + hydrogen sulfide
| cysteine lyase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC no. | 4.4.1.10 | ||||||||
| CAS no. | 9079-86-1 | ||||||||
| 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 | ||||||||
| |||||||||
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. [2]
References
- Tolosa EA, Chepurnova NK, Khomutov RM, Severin ES (1969). "Reactions catalysed by cysteine lyase from the yolk sac of chicken embryo". Biochim. Biophys. Acta. 171 (2): 369–71. doi:10.1016/0005-2744(69)90174-0. PMID 5813025.
- Malatesta M, Mori G, Acquotti D, Campanini B, Peracchi A, Antin PB, Percudani R (2020). "Birth of a pathway for sulfur metabolism in early amniote evolution". Nat Ecol Evol. 4 (9): 1239–1246. doi:10.1038/s41559-020-1232-4. PMC 8364350. PMID 32601391.