Reaction: 15-cis-phytoene + 3 acceptor = all-trans-neurosporene + 3 reduced acceptor (overall reaction)
(1a) 15-cis-phytoene + acceptor = all-trans-phytofluene + reduced acceptor
(1b) all-trans-phytofluene + acceptor = all-trans-ζ-carotene + reduced acceptor
(1c) all-trans-ζ-carotene + acceptor = all-trans-neurosporene + reduced acceptor
For diagram of reaction click here.
Other name(s): 3-step phytoene desaturase; three-step phytoene desaturase; phytoene desaturase (ambiguous); CrtI (ambiguous)
Systematic name: 15-cis-phytoene:acceptor oxidoreductase (neurosporene-forming)
Comments: This enzyme is involved in carotenoid biosynthesis and catalyses up to three desaturation steps (cf. EC 1.3.99.29 [phytoene desaturase (ζ-carotene-forming)], EC 1.3.99.30 [phytoene desaturase (3,4-didehydrolycopene-forming)], EC 1.3.99.31 [phytoene desaturase (lycopene-forming)]). The enzyme is activated by FAD. NAD+, NADP+ or ATP show no activating effect [1].
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
References:
1. Raisig, A., Bartley, G., Scolnik, P. and Sandmann, G. Purification in an active state and properties of the 3-step phytoene desaturase from Rhodobacter capsulatus overexpressed in Escherichia coli. J. Biochem. 119 (1996) 559-564. [PMID: 8830054]
2. Wang, C.W. and Liao, J.C. Alteration of product specificity of Rhodobacter sphaeroides phytoene desaturase by directed evolution. J. Biol. Chem. 276 (2001) 41161-41164. [PMID: 11526111]