EC	1.3.99.37
Accepted name:	1-hydroxy-2-isopentenylcarotenoid 3,4-desaturase
Reaction:	(1) dihydroisopentenyldehydrorhodopin + acceptor = isopentenyldehydrorhodopin + reduced acceptor (2) dihydrobisanhydrobacterioruberin + acceptor = bisanhydrobacterioruberin + reduced acceptor
Glossary:	bisanhydrobacterioruberin = (2S,2S′)-2,2′-bis(3-methylbut-2-en-1-yl)-3,4-didehydro-1,1′,2,2′-tetrahydro-ψ,ψ-carotene-1,1′-diol dihydrobisanhydrobacterioruberin = (2S,2S′)-2,2′-bis(3-methylbut-2-en-1-yl)-3,3′,4,4′-tetradehydro-1,1′,2,2′-tetrahydro-ψ,ψ-carotene-1,1′-diol dihydroisopentenyldehydrorhodopin = (2S)-2-(3-methylbut-2-en-1-yl)-3,4-didehydro-1,2-dihydro-ψ,ψ-caroten-1-ol isopentenyldehydrorhodopin = (2S)-2-(3-methylbut-2-en-1-yl)-1,2-dihydro-ψ,ψ-caroten-1-ol
Other name(s):	crtD (gene name)
Systematic name:	dihydroisopentenyldehydrorhodopin:acceptor 3,4-oxidoreductase
Comments:	The enzyme, isolated from the archaeon Haloarcula japonica, is involved in the biosynthesis of the C50 carotenoid bacterioruberin. In this pathway it catalyses the desaturation of the C-3,4 double bond in dihydroisopentenyldehydrorhodopin and the desaturation of the C-3′,4′ double bond in dihydrobisanhydrobacterioruberin.
References:	1.  Yang, Y., Yatsunami, R., Ando, A., Miyoko, N., Fukui, T., Takaichi, S. and Nakamura, S. Complete biosynthetic pathway of the C50 carotenoid bacterioruberin from lycopene in the extremely halophilic archaeon Haloarcula japonica. J. Bacteriol. 197 (2015) 1614–1623. [PMID: 25712483]
[EC 1.3.99.37 created 2015]
EC	2.5.1.150
Accepted name:	lycopene elongase/hydratase (dihydrobisanhydrobacterioruberin-forming)
Reaction:	(1) prenyl diphosphate + all-trans-lycopene + H2O = dihydroisopentenyldehydrorhodopin + diphosphate (2) prenyl diphosphate + isopentenyldehydrorhodopin + H2O = dihydrobisanhydrobacterioruberin + diphosphate
Glossary:	dihydrobisanhydrobacterioruberin = (2S,2S′)-2,2′-bis(3-methylbut-2-en-1-yl)-3,3′,4,4′-tetradehydro-1,1′,2,2′-tetrahydro-ψ,ψ-carotene-1,1′-diol = (3S,4E,6E,8E,10E,12E,14E,16E,18E,20E,22E,24E,26E,30R)-2,6,10,14,19,23,27,31-octamethyl-3,30-bis(3-methylbut-2-en-1-yl)dotriaconta-4,6,8,10,12,14,16,18,20,22,24,26-dodecaene-2,31-diol
Other name(s):	lbtA (gene name); lyeJ (gene name); dimethylallyl-diphosphate:all-trans-lycopene dimethylallyltransferase (hydrating, dihydrobisanhydrobacterioruberin-forming)
Systematic name:	prenyl-diphosphate:all-trans-lycopene prenyltransferase (hydrating, dihydrobisanhydrobacterioruberin-forming)
Comments:	The enzyme, characterized from the bacterium Dietzia sp. CQ4 and the halophilic archaea Halobacterium salinarum and Haloarcula japonica, is bifunctional. It catalyses the elongation of the C40 carotenoid all-trans-lycopene by attaching an isoprene unit at C-2 as well as the hydroxylation of the previous end of the molecule. The enzyme acts at both ends of the substrate, and combined with the action of EC 1.3.99.37, 1-hydroxy-2-isopentenylcarotenoid 3,4-desaturase, it forms the C50 carotenoid dihydrobisanhydrobacterioruberin. cf. EC 2.5.1.149, lycopene elongase/hydratase (flavuxanthin-forming).
References:	1.  Tao, L., Yao, H. and Cheng, Q. Genes from a Dietzia sp. for synthesis of C40 and C50 β-cyclic carotenoids. Gene 386 (2007) 90–97. [PMID: 17008032] 2.  Dummer, A.M., Bonsall, J.C., Cihla, J.B., Lawry, S.M., Johnson, G.C. and Peck, R.F. Bacterioopsin-mediated regulation of bacterioruberin biosynthesis in Halobacterium salinarum. J. Bacteriol. 193 (2011) 5658–5667. [PMID: 21840984] 3.  Yang, Y., Yatsunami, R., Ando, A., Miyoko, N., Fukui, T., Takaichi, S. and Nakamura, S. Complete biosynthetic pathway of the C50 carotenoid bacterioruberin from lycopene in the extremely halophilic archaeon Haloarcula japonica. J. Bacteriol. 197 (2015) 1614–1623. [PMID: 25712483]
[EC 2.5.1.150 created 2018]