IUBMB Enzyme Nomenclature


Accepted name: L-cysteine S-thiosulfotransferase

Reaction: (1) [SoxY protein]-L-cysteine + thiosulfate + 2 ferricytochrome c = [SoxY protein]-S-sulfosulfanyl-L-cysteine + 2 ferrocytochrome c + 2H+
(2) [SoxY protein]-S-sulfanyl-L-cysteine + thiosulfate + 2 ferricytochrome c = [SoxY protein]-S-(2-sulfodisulfanyl)-L-cysteine + 2 ferrocytochrome c + 2H+

Other name(s): SoxXA

Systematic name: thiosulfate:[SoxY protein]-L-cysteine thiosufotransferase

Comments: The enzyme is part of the Sox enzyme system, which participates in a bacterial thiosulfate oxidation pathway that produces sulfate. It catalyses two reactions in the pathway - early in the pathway it attaches a thiosulfate molecule to the sulfur atom of an L-cysteine of a SoxY protein; later it transfers a second thiosulfate molecule to a sulfane group that is already attached to the same cysteine residue.

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


1. Friedrich, C.G., Quentmeier, A., Bardischewsky, F., Rother, D., Kraft, R., Kostka, S. and Prinz, H. Novel genes coding for lithotrophic sulfur oxidation of Paracoccus pantotrophus GB17. J. Bacteriol. 182 (2000) 4677-4687. [PMID: 10940005]

2. Cheesman, M.R., Little, P.J. and Berks, B.C. Novel heme ligation in a c-type cytochrome involved in thiosulfate oxidation: EPR and MCD of SoxAX from Rhodovulum sulfidophilum. Biochemistry 40 (2001) 10562-10569. [PMID: 11523998]

3. Rother, D. and Friedrich, C.G. The cytochrome complex SoxXA of Paracoccus pantotrophus is produced in Escherichia coli and functional in the reconstituted sulfur-oxidizing enzyme system. Biochim. Biophys. Acta 1598 (2002) 65-73. [PMID: 12147345]

4. Bamford, V.A., Bruno, S., Rasmussen, T., Appia-Ayme, C., Cheesman, M.R., Berks, B.C. and Hemmings, A.M. Structural basis for the oxidation of thiosulfate by a sulfur cycle enzyme. EMBO J. 21 (2002) 5599-5610. [PMID: 12411478]

5. Dambe, T., Quentmeier, A., Rother, D., Friedrich, C. and Scheidig, A.J. Structure of the cytochrome complex SoxXA of Paracoccus pantotrophus, a heme enzyme initiating chemotrophic sulfur oxidation. J. Struct. Biol. 152 (2005) 229-234. [PMID: 16297640]

6. Hensen, D., Sperling, D., Truper, H.G., Brune, D.C. and Dahl, C. Thiosulphate oxidation in the phototrophic sulphur bacterium Allochromatium vinosum. Mol. Microbiol. 62 (2006) 794-810. [PMID: 16995898]

7. Grabarczyk, D.B. and Berks, B.C. Intermediates in the Sox sulfur oxidation pathway are bound to a sulfane conjugate of the carrier protein SoxYZ. PLoS One 12 (2017) e0173395. [PMID: 28257465]

[EC created 2018]

Return to EC 2.8.5 home page
Return to EC 2.8 home page
Return to EC 2 home page
Return to Enzymes home page
Return to IUBMB Biochemical Nomenclature home page