IUBMB Enzyme Nomenclature


Accepted name: cysteine desulfurase

Reaction: L-cysteine + acceptor = L-alanine + S-sulfanyl-acceptor (overall reaction)
(1a) L-cysteine + [enzyme]-cysteine = L-alanine + [enzyme]-S-sulfanylcysteine
(1b) [enzyme]-S-sulfanylcysteine + acceptor = [enzyme]-cysteine + S-sulfanyl-acceptor

For diagram of reaction click here.

Other name(s): IscS; NIFS; NifS; SufS; cysteine desulfurylase

Systematic name: L-cysteine:acceptor sulfurtransferase

Comments: A pyridoxal-phosphate protein. The sulfur from free L-cysteine is first transferred to a cysteine residue in the active site, and then passed on to various other acceptors. The enzyme is involved in the biosynthesis of iron-sulfur clusters, thio-nucleosides in tRNA, thiamine, biotin, lipoate and pyranopterin (molybdopterin) [2]. In Azotobacter vinelandii, this sulfur provides the inorganic sulfide required for nitrogenous metallocluster formation [1].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 149371-08-4


1. Zheng, L.M., White, R.H., Cash, V.L., Jack, R.F. and Dean, D.R. Cysteine desulfurase activity indicates a role for NIFS in metallocluster biosynthesis. Proc. Natl. Acad. Sci. USA 90 (1993) 2754-2758. [PMID: 8464885]

2. Mihara, H. and Esaki, N. Bacterial cysteine desulfurases: Their function and mechanisms. Appl. Microbiol. Biotechnol. 60 (2002) 12-23. [PMID: 12382038]

3. Frazzon, J. and Dean, D.R. Formation of iron-sulfur clusters in bacteria: An emerging field in bioinorganic chemistry. Curr. Opin. Chem. Biol. 7 (2003) 166-173. [PMID: 12714048]

[EC created 2003, modified 2011]

Return to EC 2.8.1 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