IUBMB Enzyme Nomenclature


Accepted name: cyclic pyranopterin phosphate synthase

Reaction: GTP = cyclic pyranopterin phosphate + diphosphate

For diagram of reaction click here and mechanism click here.

Glossary: cPMP = cyclic pyranopterin monophosphate = precursor Z = 8-amino-2,12,12-trihydroxy-4a,5a,6,9,11,11a,12,12a-octahydro[1,3,2]dioxaphosphinino[4',5':5,6]pyrano[3,2-g]pteridin-10(4H)-one 2-oxide = 8-amino-2,12,12-trihydroxy-4,4a,5a,6,9,10,11,11a,12,12a-decahydro-[1,3,2]dioxaphosphinino[4',5':5,6]pyrano[3,2-g]pteridine 2-oxide

Other name(s): MOCS1A; MoaA; MoaC; molybdenum cofactor biosynthesis protein 1; cyclic pyranopterin monophosphate synthase; GTP 8,9-lyase (cyclic pyranopterin monophosphate-forming)

Systematic name: GTP 8,9-lyase (cyclic pyranopterin phosphate-forming)

Comments: The enzyme catalyses an early step in the biosynthesis of the molybdenum cofactor (MoCo). The enzyme MoaA from bacteria and the human enzyme MOCS1A each contain two oxygen-sensitive FeS clusters. The enzyme is a member of the superfamily of S-adenosyl-L-methionine-dependent radical (radical AdoMet) enzymes. In bacteria, the reaction is catalysed by MoaA and requires the action of MoaC. The latter protein is equivalent to the C-terminal domain of the eukaryotic enzyme MOCS1A which does not need further protein components to perform the reaction.

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


1. Rieder, C., Eisenreich, W., O'Brien, J., Richter, G., Götze, E., Boyle, P., Blanchard, S., Bacher, A. and Simon, H. Rearrangement reactions in the biosynthesis of molybdopterin - an NMR study with multiply 13C/15N labelled precursors. Eur. J. Biochem. 255 (1998) 24-36. [PMID: 9692897]

2. Wuebbens, M.M. and Rajagopalan, K.V. Investigation of the early steps of molybdopterin biosynthesis in Escherichia coli through the use of in vivo labeling studies. J. Biol. Chem. 270 (1995) 1082-1087. [PMID: 7836363]

3. Hänzelmann, P., Hernandez, H.L., Menzel, C., Garcia-Serres, R., Huynh, B.H., Johnson, M.K., Mendel, R.R. and Schindelin, H. Characterization of MOCS1A, an oxygen-sensitive iron-sulfur protein involved in human molybdenum cofactor biosynthesis. J. Biol. Chem. 279 (2004) 34721-34732. [PMID: 15180982]

4. Hänzelmann, P. and Schindelin, H. Crystal structure of the S-adenosylmethionine-dependent enzyme MoaA and its implications for molybdenum cofactor deficiency in humans. Proc. Natl. Acad. Sci. USA 101 (2004) 12870-12875. [PMID: 15317939]

5. Sanishvili, R., Beasley, S., Skarina, T., Glesne, D., Joachimiak, A., Edwards, A. and Savchenko, A. The crystal structure of Escherichia coli MoaB suggests a probable role in molybdenum cofactor synthesis. J. Biol. Chem. 279 (2004) 42139-42146. [PMID: 15269205]

6. Hänzelmann, P. and Schindelin, H. Binding of 5'-GTP to the C-terminal FeS cluster of the radical S-adenosylmethionine enzyme MoaA provides insights into its mechanism. Proc. Natl. Acad. Sci. USA 103 (2006) 6829-6834. [PMID: 16632608]

7. Lees, N.S., Hänzelmann, P., Hernandez, H.L., Subramanian, S., Schindelin, H., Johnson, M.K. and Hoffman, B.M. ENDOR spectroscopy shows that guanine N1 binds to [4Fe-4S] cluster II of the S-adenosylmethionine-dependent enzyme MoaA: mechanistic implications. J. Am. Chem. Soc. 131 (2009) 9184-9185. [PMID: 19566093]

[EC created 2011]

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