1-hydroxycarotenoid 3,4-desaturase;
CrtD;
hydroxyneurosporene desaturase;
carotenoid 3,4-dehydrogenase;
1-hydroxy-carotenoid 3,4-dehydrogenase

Oxidoreductases;
Acting on the CH-CH group of donors;
With other acceptors

1-hydroxy-1,2-dihydrolycopene:acceptor oxidoreductase

1-hydroxy-1,2-dihydrolycopene + acceptor = 1-hydroxy-3,4-didehydro-1,2-dihydrolycopene + reduced acceptor [RN:R07520]

R07520;
(other) R07523 R07534

1-hydroxy-1,2-dihydrolycopene [CPD:C19795];
acceptor [CPD:C00028]

The enzymes from Rubrivivax gelatinosus and Rhodobacter sphaeroides prefer the acyclic carotenoids (e.g. 1-hydroxy-1,2-dihydroneurosporene, 1-hydroxy-1,2-dihydrolycopene) as substrates. The conversion rate for the 3,4-desaturation of the monocyclic 1'-hydroxy-1',2'-dihydro-gamma-carotene is lower [2,3]. The enzyme from the marine bacterium strain P99-3 shows high activity with the monocyclic carotenoid 1'-hydroxy-1',2'-dihydro-gamma-carotene [1]. The enzyme from Rhodobacter sphaeroides utilizes molecular oxygen as the electron acceptor in vitro [3]. However, oxygen is unlikely to be the natural electron acceptor under anaerobic conditions.

1  [PMID:15251462]

Teramoto M, Rahlert N, Misawa N, Sandmann G.

1-Hydroxy monocyclic carotenoid 3,4-dehydrogenase from a marine bacterium that produces myxol.

FEBS. Lett. 570 (2004) 184-8.

2  [PMID:10880364]

Steiger S, Astier C, Sandmann G

Substrate specificity of the expressed carotenoid 3,4-desaturase from Rubrivivax  gelatinosus reveals the detailed reaction sequence to spheroidene and spirilloxanthin.

Biochem. J. 349 (2000) 635-40.

3  [PMID:9393712]

Albrecht M, Ruther A, Sandmann G.

Purification and biochemical characterization of a hydroxyneurosporene desaturase involved in the biosynthetic pathway of the carotenoid spheroidene in Rhodobacter sphaeroides.

J. Bacteriol. 179 (1997) 7462-7.