:Carotenoid isomerooxygenase

{{Infobox enzyme

| Name = Carotenoid isomerooxygenase

| EC_number = 1.13.11.65

| CAS_number =

| GO_code =

| image =

| width =

| caption =

}}

Carotenoid isomerooxygenase ({{EC number|1.13.11.65}}, ninaB (gene)) is an enzyme with systematic name zeaxanthin:oxygen 15,15'-oxidoreductase (bond-cleaving, cis-isomerizing).{{cite journal | vauthors = Oberhauser V, Voolstra O, Bangert A, von Lintig J, Vogt K | title = NinaB combines carotenoid oxygenase and retinoid isomerase activity in a single polypeptide | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 105 | issue = 48 | pages = 19000–5 | date = December 2008 | pmid = 19020100 | pmc = 2596218 | doi = 10.1073/pnas.0807805105 | bibcode = 2008PNAS..10519000O | doi-access = free }} This enzyme catalyses the following chemical reaction

: zeaxanthin + O₂ $\backslash rightleftharpoons$ (3R)-11-cis-3-hydroxyretinal + (3R)-all-trans-3-hydroxyretinal

The enzyme from the moth Galleria mellonella and the fruit fly Drosophila melanogaster takes part in the synthesis of retinal .