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B6db activities:
Description Cysteine synthase.
Alternative names O-acetylserine (thiol)-lyase;
O-acetylserine sulfhydrylase;
OAS sulfhydrylase.
Catalyzed reaction O3-acetyl-L-serine + H(2)S = L-cysteine + acetate.
Cofactor Pyridoxal-phosphate.
Comments -!- Some alkyl thiols, cyanide, pyrazole and some other heterocyclic compounds can act as acceptors.
-!- Not identical with EC, EC or EC
-!- Formerly EC
Several bacteria contain two cysteine synthase isozymes: O-acetylserine sulfhydrylase A (cysK) and O-acetylserine sulfhydrylase B (cysM). In contrast to O-acetylserine sulfhydrylase A, O-acetylserine sulfhydrylase B is preferentially used for cysteine biosynthesis during anaerobic growth and is able to utilize thiosulfate as a substrate.

In contrast to the enzymes grouped under this EC number, the enzyme from Aeropyrum pernix acts on both O-phospho-L-serine and O3-acetyl-L-serine, and it has hence been given a different EC number (

Prosite PROSITE; PDOC00700;
PDB 1OAS; 1FCJ; 1O58; 1D6S; 2BHS;
Organisms -Eubacteria -Archea -Plants -Fungi

Family (46)
Links Enzyme (activities)
BRENDA (activities)
KEGG (pathways)
PLPMDB (PLP mutants)
 Yafuso JT1, Negi VS, Bingham JP, Borthakur D. (2014) An O-Acetylserine (thiol) Lyase from Leucaena leucocephala Is a Cysteine Synthase But Not a Mimosine Synthase Appl Microbiol Biotechnol. 173 1157-68.

 Bogicevic B, Berthoud H, Portmann R, Meile L, Irmler S. (2012) CysK from Lactobacillus casei encodes a protein with O-acetylserine sulfhydrylase and cysteine desulfurization activity. Appl Microbiol Biotechnol. 94 1209-20.

 Tahir J, Watanabe M, Jing HC, Hunter DA, Tohge T, Nunes-Nesi A, Brotman Y, Fernie AR, Hoefgen R, Dijkwel PP. (2012) Activation of R-mediated innate immunity and disease susceptibility is affected by mutations in a cytosolic O-acetylserine (thiol) lyase in Arabidopsis Plant J. 73 .

 Zheng C, Nie L, Qian L, Wang Z, Liu G, Liu J. (2009) K30, H150, and H168 Are Essential Residues for Coordinating Pyridoxal 5'-Phosphate of O-Acetylserine Sulfhydrylase from Acidithiobacillus ferrooxidans Curr Microbiol 60 461-5.

 Claus, M.T.; Zocher, G.E.; Maier, T.H.; Schulz, G.E. (2005) Structure of the O-Acetylserine Sulfhydrylase Isoenzyme CysM from Escherichia coli Biochemistry 44 8620-6.

 Fujita, Y.; Takegawa, K. (2004) Characterization of two genes encoding putative cysteine synthase required for cysteine biosynthesis in Schizosaccharomyces pombe Biosci Biotechnol Biochem 68 306-11.

 Lithgow, J.K., Hayhurst, E.J.; Cohen, G.; Aharonowitz, Y.; Foster, S.J. (2004) Role of a cysteine synthase in Staphylococcus aureus J Bacteriol 186 1579-90.

 Miller MD, Schwarzenbacher R, von Delft F, Abdubek P, Ambing E, et al. (2004) Crystal structure of a tandem cystathionine--synthase (CBS) domain protein (TM0935) from Thermotoga maritima at 1.87 resolution Proteins 57 213 - 217.

 Saavedra CP, Encinas MV, Araya MA, Perez JM, Tantalean JC, Fuentes DE, Calderon IL, Pichuantes SE, Vasquez CC. (2004) Biochemical characterization of a thermostable cysteine synthase from Geobacillus stearothermophilus V Biochimie 86 481-5.

 Omura H, Kuroda M, Kobayashi M, Shimizu S, Yoshida T, Nagasawa T. (2003) Purification, characterization and gene cloning of thermostable O-acetyl-L-serine sulfhydrylase forming beta-cyano-L-alanine J Biosci Bioeng 95 470-5.

 Mizuno, Y.; Miyashita, Y.; Yamagata, S.; Iwama, T.; Akamatsu, T. (2002) Cysteine synthase of an extremely thermophilic bacterium, Thermus thermophilus HB8 Biosci Biotechnol Biochem 66 549-57.

 Borup, B., Ferry, J.G. (2000) O-Acetylserine sulfhydrylase from Methanosarcina thermophila J Bacteriol 182 45-50.

 Jost, R.; Berkowitz, O.; Wirtz, M.; Hopkins, L.; Hawkesford, M. J.; Hell, R. (2000) Genomic and functional characterization of the oas gene family encoding O-acetylserine (thiol) lyases, enzymes catalyzing the final step in cysteine biosynthesis in Arabidopsis thaliana Gene 253 237-47.

 Burkhard, P.; Rao, G. S.; Hohenester, E.; Schnackerz, K. D.; Cook, P. F.; Jansonius, J. N. (1998) Three-dimensional structure of O-acetylserine sulfhydrylase from Salmonella typhimurium J Mol Biol 283 121-33.

 Muller, R.; Kuttler, E.; Lanz, C.; Drewke, C.; Schmidt, K. (1996) Isolation of a gene encoding cysteine synthase from Flavobacterium K3-15 FEMS Microbiol Lett 136 305-8.

 Rolland, N.; Droux, M.; Lebrun, M.; Douce, R. (1993) O-acetylserine(thiol)lyase from spinach (Spinacia oleracea L.) leaf: cDNA cloning, characterization, and overexpression in Escherichia coli of the chloroplast isoform Arch Biochem Biophys 300 213-22.

 Owais, W.M.; Gharaibeh, R. (1990) Cloning of the E. coli O-acetylserine sulfhydrylase gene: ability of the clone to produce a mutagenic product from azide and O-acetylserine Mutat Res 245 151-5.

Articles on
last changed 2010/01/27 18:07

B6db activities