IUBMB Enzyme Nomenclature


Accepted name: phytoene desaturase (neurosporene-forming)

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 [phytoene desaturase (ζ-carotene-forming)], EC [phytoene desaturase (3,4-didehydrolycopene-forming)], EC [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:


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]

[EC created 2011]

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