Reaction: 1-hydroxy-1,2-dihydrolycopene + acceptor = 1-hydroxy-3,4-didehydro-1,2-dihydrolycopene + reduced acceptor
For diagram of reaction click here or click here
Other name(s): CrtD; hydroxyneurosporene desaturase; carotenoid 3,4-dehydrogenase; 1-hydroxy-carotenoid 3,4-dehydrogenase
Systematic name: 1-hydroxy-1,2-dihydrolycopene:acceptor oxidoreductase
Comments: 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-γ-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-γ-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.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:
References:
1. Teramoto, M., Rahlert, N., Misawa, N. and Sandmann, G. 1-Hydroxy monocyclic carotenoid 3,4-dehydrogenase from a marine bacterium that produces myxol. FEBS Lett. 570 (2004) 184-188. [PMID: 15251462]
2. Steiger, S., Astier, C. and 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) 635-640. [PMID: 10880364]
3. Albrecht, M., Ruther, A. and 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) 7462-7467. [PMID: 9393712]