phytoene desaturase (lycopene-forming);
4-step phytoene desaturase;
four-step phytoene desaturase;
phytoene desaturase (ambiguous);
CrtI (ambiguous)

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

15-cis-phytoene:acceptor oxidoreductase (lycopene-forming)

15-cis-phytoene + 4 acceptor = all-trans-lycopene + 4 reduced acceptor (overall reaction) [RN:R09716];
(1a) 15-cis-phytoene + acceptor = all-trans-phytofluene + reduced acceptor [RN:R09692];
(1b) all-trans-phytofluene + acceptor = all-trans-zeta-carotene + reduced acceptor [RN:R04787];
(1c) all-trans-zeta-carotene + acceptor = all-trans-neurosporene + reduced acceptor [RN:R04798];
(1d) all-trans-neurosporene + acceptor = all-trans-lycopene + reduced acceptor [RN:R04800]

R04787 R04798 R04800 R09692 R09716

15-cis-phytoene [CPD:C05421];
acceptor [CPD:C00028];
all-trans-phytofluene [CPD:C05414];
all-trans-zeta-carotene [CPD:C05430];
all-trans-neurosporene [CPD:C05431]

Requires FAD. The enzyme is involved in carotenoid biosynthesis and catalyses up to four desaturation steps (cf. EC 1.3.99.28 [phytoene desaturase (neurosporene-forming)], EC 1.3.99.29 [phytoene desaturase (zeta-carotene-forming)] and EC 1.3.99.30 [phytoene desaturase (3,4-didehydrolycopene-forming)]).

1  [PMID:1400305]

Fraser PD, Misawa N, Linden H, Yamano S, Kobayashi K, Sandmann G

Expression in Escherichia coli, purification, and reactivation of the recombinant Erwinia uredovora phytoene desaturase.

J. Biol. Chem. 267 (1992) 19891-5.