IUBMB Enzyme Nomenclature


Accepted name: S-sulfo-L-cysteine synthase (3-phospho-L-serine-dependent)

Reaction: O-phospho-L-serine + thiosulfate = S-sulfo-L-cysteine + phosphate

Other name(s): cysK2 (gene name); thiosulfate:3-phospho-L-serine thiosulfotransferase

Systematic name: thiosulfate:3-phospho-L-serine thiosulfonotransferase

Comments: The enzyme, which has been characterized from the bacterium Mycobacterium tuberculosis, has no activity with O-acetyl-L-serine. Requires pyridoxal 5'-phosphate. cf. EC, S-sulfo-L-cysteine synthase (O-acetyl-L-serine-dependent).

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:


1. Steiner, E.M., Both, D., Lossl, P., Vilaplana, F., Schnell, R. and Schneider, G. CysK2 from Mycobacterium tuberculosis is an O-phospho-L-serine-dependent S-sulfocysteine synthase. J. Bacteriol. 196 (2014) 3410-3420. [PMID: 25022854]

[EC created 2018]

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