:1-Hydroxycarotenoid 3,4-desaturase

{{Short description|Class of enzymes}}

{{Infobox enzyme

| Name = 1-hydroxycarotenoid 3,4-desaturase

| EC_number = 1.3.99.27

| CAS_number =

| GO_code =

| image =

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1-Hydroxycarotenoid 3,4-desaturase ({{EC number|1.3.99.27}}, CrtD, hydroxyneurosporene desaturase, carotenoid 3,4-dehydrogenase, 1-hydroxy-carotenoid 3,4-dehydrogenase) is an enzyme with systematic name 1-hydroxy-1,2-dihydrolycopene:acceptor oxidoreductase.{{cite journal | vauthors = Teramoto M, Rählert N, Misawa N, Sandmann G | title = 1-Hydroxy monocyclic carotenoid 3,4-dehydrogenase from a marine bacterium that produces myxol | journal = FEBS Letters | volume = 570 | issue = 1-3 | pages = 184–8 | date = July 2004 | pmid = 15251462 | doi = 10.1016/j.febslet.2004.05.085 | doi-access = free }}{{cite journal | vauthors = Steiger S, Astier C, Sandmann G | title = Substrate specificity of the expressed carotenoid 3,4-desaturase from Rubrivivax gelatinosus reveals the detailed reaction sequence to spheroidene and spirilloxanthin | journal = The Biochemical Journal | volume = 349 | issue = Pt 2 | pages = 635–40 | date = July 2000 | pmid = 10880364 | pmc = 1221188 | doi = 10.1042/0264-6021:3490635 }}{{cite journal | vauthors = Albrecht M, Ruther A, Sandmann G | title = Purification and biochemical characterization of a hydroxyneurosporene desaturase involved in the biosynthetic pathway of the carotenoid spheroidene in Rhodobacter sphaeroides | journal = Journal of Bacteriology | volume = 179 | issue = 23 | pages = 7462–7 | date = December 1997 | pmid = 9393712 | pmc = 179698 }} This enzyme catalyses the following chemical reaction

: 1-hydroxy-1,2-dihydrolycopene + acceptor $\backslash rightleftharpoons$ 1-hydroxy-3,4-didehydro-1,2-dihydrolycopene + reduced acceptor

The enzymes from Rubrivivax gelatinosus and Rhodobacter sphaeroides acts primarily on acyclic carotenoids.