IUBMB Enzyme Nomenclature


Accepted name: 7-deoxycylindrospermopsin hydroxylase

Reaction: (1) 7-deoxycylindrospermopsin + 2-oxoglutarate + O2 = cylindrospermopsin + succinate + CO2
(2) 7-deoxycylindrospermopsin + 2-oxoglutarate + O2 = 7-epi-cylindrospermopsin + succinate + CO2

Glossary: cylindrospermopsin = (2aS,3R,4S,5aS,7R)-7-[(R)-(2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-yl)(hydroxy)methyl]-3-methyl-2a,3,4,5,5a,6,7,8-octahydro-2H-1,8,8b-triazaacenaphthylen-4-yl hydrogen sulfate

Other name(s): cyrI (gene name)

Systematic name: 7-deoxycylindrospermopsin, 2-oxoglutarate:oxygen oxidoreductase (7-hydroxylating)

Comments: Requires iron((II). The enzyme, found in some cyanobacterial species, catalyses the last step in the biosynthesis of the toxins cylindrospermopsin and 7-epi-cylindrospermopsin. The ratio of the two products differs among different strains.

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


1. Mazmouz, R., Chapuis-Hugon, F., Pichon V., Mejean, A., and Ploux, O. The last step of the biosynthesis of the cyanotoxins cylindrospermopsin and 7-epi-cylindrospermopsin is catalysed by CyrI, a 2-oxoglutarate-dependent iron oxygenase. Chem. Biochem. 12 (2011) 858-862.

2. Mazmouz, R., Essadik, I., Hamdane, D., Mejean, A. and Ploux, O. Characterization of CyrI, the hydroxylase involved in the last step of cylindrospermopsin biosynthesis: Binding studies, site-directed mutagenesis and stereoselectivity. Arch. Biochem. Biophys. 647 (2018) 1-9. [PMID: 29653078]

[EC created 2019]

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