Open Access Articles- Top Results for Cysteine synthase

Cysteine synthase

cysteine synthase
EC number
CAS number 37290-89-4
IntEnz IntEnz view
ExPASy NiceZyme view
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / EGO

In enzymology, a cysteine synthase (EC is an enzyme that catalyzes the chemical reaction

O3-acetyl-L-serine + hydrogen sulfide <math>\rightleftharpoons</math> L-cysteine + acetate

Thus, the two substrates of this enzyme are O3-acetyl-L-serine and hydrogen sulfide, whereas its two products are L-cysteine and acetate.

This enzyme belongs to the family of transferases, 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. This enzyme participates in 3 metabolic pathways: cysteine metabolism, selenoamino acid metabolism, and sulfur metabolism. It employs one cofactor, pyridoxal phosphate.

Structural studies

As of late 2007, 12 structures have been solved for this class of enzymes, with PDB accession codes 1O58, 1VE1, 1Y7L, 1Z7W, 1Z7Y, 2BHS, 2BHT, 2EGU, 2ISQ, 2Q3B, 2Q3C, and 2Q3D.


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  • 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. PMID 11412097. doi:10.1021/bi015511s. 
  • 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. PMID 10995767. doi:10.1074/jbc.M007015200. 

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