Cysteine synthase
| Cysteine synthase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC no. | 2.5.1.47 | ||||||||
| CAS no. | 37290-89-4 | ||||||||
| Databases | |||||||||
| BRENDA | enzyme data | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | enzyme entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| Rhea | reactions | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
Cysteine synthase (EC 2.5.1.47) is an enzyme that catalyzes the chemical reaction
The two substrates of this enzyme first characterised from Salmonella typhimurium are O-acetylserine and hydrogen sulfide (H2S). Its products are acetic acid and cysteine.[1][2]
The enzyme can transfer the 2-amino-2-carboxyethyl group to other nucleophiles. For example, it has been found to be involved in the final step of the biosynthesis of quisqualic acid in the vine Quisqualis indica.[3] However, it has different selectivity to the enzyme uracilylalanine synthase, which also converts O-acetylserine to amino acid derivatives.[4] It uses pyridoxal phosphate as a cofactor.[5] Chloride and sulfate ions can act as inhibitors of the enzyme by binding at an allosteric site.[6]
This enzyme is a transferase, specifically those transferring aryl or alkyl groups other than methyl groups. The systematic name of this enzyme class is O3-acetyl-L-serine:hydrogen-sulfide 2-amino-2-carboxyethyltransferase. Other names in common use include O-acetyl-L-serine sulfhydrylase, O-acetyl-L-serine sulfohydrolase, O-acetylserine (thiol)-lyase, O-acetylserine (thiol)-lyase A, O-acetylserine sulfhydrylase, O3-acetyl-L-serine acetate-lyase (adding hydrogen-sulfide), acetylserine sulfhydrylase, cysteine synthetase, S-sulfocysteine synthase, 3-O-acetyl-L-serine:hydrogen-sulfide, and 2-amino-2-carboxyethyltransferase.[7] This enzyme participates in 3 metabolic pathways: cysteine metabolism, selenoamino acid metabolism, and sulfur metabolism.
Structural studies
As of late 2007, 12 structures have been solved for this class of enzymes, with PDB accession codes PDB: 1O58, PDB: 1VE1, PDB: 1Y7L, PDB: 1Z7W, PDB: 1Z7Y, PDB: 2BHS, PDB: 2BHT, PDB: 2EGU, PDB: 2ISQ, PDB: 2Q3B, PDB: 2Q3C, and PDB: 2Q3D.
References
- ↑ Becker MA, Kredich NM, Tomkins GM (1969). "The purification and characterization of O-acetylserine sulfhydrylase-A from Salmonella typhimurium". J. Biol. Chem. 244 (9): 2418–27. doi:10.1016/S0021-9258(19)78240-4. PMID 4891157.
- ↑ Hara S, Payne MA, Schnackerz KD, Cook PF (1990). "A rapid purification procedure and computer-assisted sulfide ion selective electrode assay for O-acetylserine sulfhydrylase from Salmonella typhimurium". Protein Expr. Purif. 1 (1): 70–6. doi:10.1016/1046-5928(90)90048-4. PMID 2152186.
- ↑ Murakoshi I, Kaneko M, Koide C, Ikegami F (1986). "Enzymatic-synthesis of the neuroexcitatory amino-acid quisqualic by cysteine synthase". Phytochemistry. 25 (12): 2759–2763. doi:10.1016/S0031-9422(00)83736-X.
- ↑ Ikegami F, Kaneko M, Lambein F, Kuo Y-H, Murakoshi I (1987). "Difference between uracilylalanine synthases and cysteine synthases in Pisum sativum". Phytochemistry. 26 (10): 2699–2704. Bibcode:1987PChem..26.2699I. doi:10.1016/S0031-9422(00)83575-X.
- ↑ Schnackerz KD, Hazlett TL, Gratton E, Mozzarelli A (2000). "Role of pyridoxal 5'-phosphate in the structural stabilization of O-acetylserine sulfhydrylase". J. Biol. Chem. 275 (51): 40244–51. doi:10.1074/jbc.M007015200. PMID 10995767.
- ↑ Tai CH, Burkhard P, Gani D, Jenn T, Johnson C, Cook PF (2001). "Characterization of the allosteric anion-binding site of O-acetylserine sulfhydrylase". Biochemistry. 40 (25): 7446–52. doi:10.1021/bi015511s. PMID 11412097.
- ↑ Enzyme 2.5.1.47 at KEGG Pathway Database.