Phytoene desaturase (34-didehydrolycopene-forming) (EC 1.3.99.30 5-step phytoene desaturase five-step phytoene desaturase phytoene desaturase (ambiguous) Al-1) is an enzyme with system name 15-cis-phytoene:acceptor oxidoreductase (34-didehydrolycopene-forming).