Reaction: molybdenum cofactor + L-cysteine + reduced acceptor + 2 H+ = thio-molybdenum cofactor + L-alanine + H2O + oxidized acceptor
For diagram of reaction click here.
Glossary: molybdenum cofactor = MoCo = MoO2(OH)Dtpp-mP = {[(5aR,8R,9aR)-2-amino-4-oxo-6,7-bis(sulfanyl-κS)-1,5,5a,8,9a,10-hexahydro-4H-pyrano[3,2-g]pteridin-8-yl]methyl dihydrogenato(2–) phosphate}(dioxo)molybdate
Other name(s): molybdenum cofactor sulfurase; ABA3; HMCS; MoCo sulfurase; MoCo sulfurtransferase
Systematic name: L-cysteine:molybdenum cofactor sulfurtransferase
Comments: Contains pyridoxal phosphate. Replaces the equatorial oxo ligand of the molybdenum by sulfur via an enzyme-bound persulfide. The reaction occurs in prokaryotes and eukaryotes but MoCo sulfurtransferases are only found in eukaryotes. In prokaryotes the reaction is catalysed by two enzymes: cysteine desulfurase (EC 2.8.1.7), which is homologous to the N-terminus of eukaryotic MoCo sulfurtransferases, and a molybdo-enzyme specific chaperone which binds the MoCo and acts as an adapter protein.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Bittner, F., Oreb, M. and Mendel, R.R. ABA3 is a molybdenum cofactor sulfurase required for activation of aldehyde oxidase and xanthine dehydrogenase in Arabidopsis thaliana. J. Biol. Chem. 276 (2001) 40381-40384. [PMID: 11553608]
2. Heidenreich, T., Wollers, S., Mendel, R.R. and Bittner, F. Characterization of the NifS-like domain of ABA3 from Arabidopsis thaliana provides insight into the mechanism of molybdenum cofactor sulfuration. J. Biol. Chem. 280 (2005) 4213-4218. [PMID: 15561708]
3. Wollers, S., Heidenreich, T., Zarepour, M., Zachmann, D., Kraft, C., Zhao, Y., Mendel, R.R. and Bittner, F. Binding of sulfurated molybdenum cofactor to the C-terminal domain of ABA3 from Arabidopsis thaliana provides insight into the mechanism of molybdenum cofactor sulfuration. J. Biol. Chem. 283 (2008) 9642-9650. [PMID: 18258600]