EC - [CysO sulfur-carrier protein]-thiocarboxylate-dependent cysteine synthase

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IntEnz Enzyme Nomenclature


Accepted name:
[CysO sulfur-carrier protein]-thiocarboxylate-dependent cysteine synthase
Other names:
CysO-thiocarboxylate-dependent cysteine synthase
Systematic name:
O-phospho-L-serine:thiocarboxylated [CysO sulfur-carrier protein] 2-amino-2-carboxyethyltransferase




A pyridoxal-phosphate protein. The enzyme participates in an alternative pathway for L-cysteine biosynthesis that involves a protein-bound thiocarboxylate as the sulfide donor. The enzyme from the bacterium Mycobacterium tuberculosis also has very low activity with O3-acetyl-L-serine (cf. EC, O-phosphoserine sulfhydrylase).

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB


  1. O'Leary, S. E., Jurgenson, C. T., Ealick, S. E., Begley, T. P.
    O-phospho-L-serine and the thiocarboxylated sulfur carrier protein CysO-COSH are substrates for CysM, a cysteine synthase from Mycobacterium tuberculosis.
    Biochemistry 47 : 11606-11615 (2008). [PMID: 18842002]
  2. Jurgenson, C. T., Burns, K. E., Begley, T. P., Ealick, S. E.
    Crystal structure of a sulfur carrier protein complex found in the cysteine biosynthetic pathway of Mycobacterium tuberculosis.
    Biochemistry 47 : 10354-10364 (2008). [PMID: 18771296]
  3. Ågren, D., Schnell, R., Oehlmann, W., Singh, M., Schneider, G.
    Cysteine synthase (CysM) of Mycobacterium tuberculosis is an O-phosphoserine sulfhydrylase: evidence for an alternative cysteine biosynthesis pathway in mycobacteria.
    J. Biol. Chem. 283 : 31567-31574 (2008). [PMID: 18799456]
  4. Ågren, D., Schnell, R., Schneider, G.
    The C-terminal of CysM from Mycobacterium tuberculosis protects the aminoacrylate intermediate and is involved in sulfur donor selectivity.
    FEBS Lett. 583 : 330-336 (2009). [PMID: 19101553]

[EC created 2013]