IUBMB Enzyme Nomenclature


Accepted name: carotenoid isomerooxygenase

Reaction: zeaxanthin + O2 = (3R)-11-cis-3-hydroxyretinal + (3R)-all-trans-3-hydroxyretinal

For diagram of reaction click here.

Other name(s): ninaB (gene name)

Systematic name: zeaxanthin:oxygen 15,15'-oxidoreductase (bond-cleaving, cis-isomerizing)

Comments: The enzyme, characterized from the moth Galleria mellonella and the fruit fly Drosophila melanogaster, is involved in the synthesis of retinal from dietary caroteoids in insects. The enzyme accepts different all-trans carotenoids, including β-carotene, α-carotene and lutein, and catalyses the symmetrical cleavage of the carotenoid and the simultaneous isomerization of only one of the products to a cis configuration. When the substrate is hydroxylated only in one side (as in cryptoxanthin), the enzyme preferentially isomerizes the hydroxylated part of the molecule.

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


1. Oberhauser, V., Voolstra, O., Bangert, A., von Lintig, J. and Vogt, K. NinaB combines carotenoid oxygenase and retinoid isomerase activity in a single polypeptide. Proc. Natl. Acad. Sci. USA 105 (2008) 19000-19005. [PMID: 19020100]

[EC created 2012 as EC, transferred 2012 to EC]

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