IUBMB Enzyme Nomenclature


Accepted name: (–)-cyclopenine synthase

Reaction: (1) cyclopeptine + 2-oxoglutarate + O2 = dehydrocyclopeptine + succinate + CO2 + H2O
(2) dehydrocyclopeptine + 2-oxoglutarate + O2 = (–)-cyclopenine + succinate + CO2

For reaction pathway click here.

Glossary: cyclopeptine = (3S)-3-benzyl-4-methyl-3,4-dihydro-1H-1,4-benzodiazepine-2,5-dione
(–)-cyclopenine = (3S,3'R)-4-methyl-3'-phenyl-1H-spiro[1,4-benzodiazepine-3,2'-oxirane]-2,5-dione

Other name(s): asqJ (gene name)

Systematic name: cyclopeptine,2-oxoglutarate:oxygen oxidoreductase ((–)-cyclopenine-forming)

Comments: This fungal enzyme is involved in the biosynthesis of quinolone compounds. it catalyses two oxidation reactions: the first reaction results in a desaturation; the second reaction is a monooxygenation of the double bond, forming an epoxide. The enzyme is also active with 4'-methoxycyclopeptine.

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


1. Nover, L. and Luckner, M. Mixed functional oxygenations during the biosynthesis of cyclopenin and cyclopenol, benzodiazepine alkaloids of Penicillium cyclopium westling. Incorporation of molecular oxygen and NIH-shift. FEBS Lett. 3 (1969) 292-296. [PMID: 11947032]

2. Ishikawa, N., Tanaka, H., Koyama, F., Noguchi, H., Wang, C.C., Hotta, K. and Watanabe, K. Non-heme dioxygenase catalyzes atypical oxidations of 6,7-bicyclic systems to form the 6,6-quinolone core of viridicatin-type fungal alkaloids. Angew. Chem. Int. Ed. Engl. 53 (2014) 12880-12884. [PMID: 25251934]

3. Brauer, A., Beck, P., Hintermann, L. and Groll, M. Structure of the dioxygenase AsqJ: Mechanistic insights into a one-pot multistep quinolone antibiotic biosynthesis. Angew. Chem. Int. Ed. Engl. 55 (2016) 422-426. [PMID: 26553478]

4. Chang, W.C., Li, J., Lee, J.L., Cronican, A.A. and Guo, Y. Mechanistic investigation of a non-heme iron enzyme catalyzed epoxidation in (–)-4'-methoxycyclopenin biosynthesis. J. Am. Chem. Soc. 138 (2016) 10390-10393. [PMID: 27442345]

5. Song, X., Lu, J. and Lai, W. Mechanistic insights into dioxygen activation, oxygen atom exchange and substrate epoxidation by AsqJ dioxygenase from quantum mechanical/molecular mechanical calculations. Phys Chem Chem Phys 19 (2017) 20188-20197. [PMID: 28726913]

6. Liao, H.J., Li, J., Huang, J.L., Davidson, M., Kurnikov, I., Lin, T.S., Lee, J.L., Kurnikova, M., Guo, Y., Chan, N.L. and Chang, W.C. Insights into the desaturation of cyclopeptin and its C3 epimer catalyzed by a non-heme Iron enzyme: structural characterization and mechanism elucidation. Angew. Chem. Int. Ed. Engl. 57 (2018) 1831-1835. [PMID: 29314482]

7. Mader, S.L., Brauer, A., Groll, M. and Kaila, V.RI. Catalytic mechanism and molecular engineering of quinolone biosynthesis in dioxygenase AsqJ. Nat. Commun. 9 (2018) 1168. [PMID: 29563492]

8. Wojdyla, Z. and Borowski, T. On how the binding cavity of AsqJ dioxygenase controls the desaturation reaction regioselectivity: a QM/MM study. J. Biol. Inorg. Chem. 23 (2018) 795-808. [PMID: 29876666]

9. Li, J., Liao, H.J., Tang, Y., Huang, J.L., Cha, L., Lin, T.S., Lee, J.L., Kurnikov, I.V., Kurnikova, M.G., Chang, W.C., Chan, N.L. and Guo, Y. Epoxidation catalyzed by the nonheme iron(II)- and 2-oxoglutarate-dependent oxygenase, AsqJ: mechanistic elucidation of oxygen atom transfer by a ferryl intermediate. J. Am. Chem. Soc. 142 (2020) 6268-6284. [PMID: 32131594]

10. Tang, H., Tang, Y., Kurnikov, I.V., Liao, H.J., Chan, N.L., Kurnikova, M.G., Guo, Y. and Chang, W.C. Harnessing the substrate promiscuity of dioxygenase AsqJ and developing efficient chemoenzymatic synthesis for quinolones. ACS Catal. 11 (2021) 7186-7192. [PMID: 35721870]

[EC created 2022]

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