Oxidoreductases;
Acting on paired donors, with incorporation or reduction of molecular oxygen;
With oxidation of a pair of donors resulting in the reduction of O2 to two molecules of water
BRITE hierarchy

ergosta-5,7,24(28)-trien-3beta-ol,NADPH:oxygen oxidoreductase (22,23-dehydrogenating)

ergosta-5,7,24(28)-trien-3beta-ol + NADPH + H+ + O2 = ergosta-5,7,22,24(28)-tetraen-3beta-ol + NADP+ + 2 H2O [RN:R07506]

R07506;
(other) R07489 R11097
Reaction

ergosta-5,7,24(28)-trien-3beta-ol [CPD:C15778];
NADPH [CPD:C00005];
H+ [CPD:C00080];
O2 [CPD:C00007]

A heme-thiolate protein (P-450). The enzyme, found in yeast and plants, catalyses the introduction of a double bond between the C-22 and C-23 carbons of certain sterols. In yeast the enzyme acts on ergosta-5,7,24(28)-trien-3beta-ol, a step in the biosynthesis of ergosterol. The enzyme from the plant Arabidopsis thaliana acts on sitosterol and 24-epi-campesterol, producing stigmasterol and brassicasterol, respectively.

EC 1.14.19.41 created 2015

1  [PMID:8543054]

Kelly SL, Lamb DC, Corran AJ, Baldwin BC, Parks LW, Kelly DE

Purification and reconstitution of activity of Saccharomyces cerevisiae P450 61,  a sterol delta 22-desaturase.

FEBS Lett 377:217-20 (1995)
DOI:10.1016/0014-5793(95)01342-3

2  [PMID:8635732]

Skaggs BA, Alexander JF, Pierson CA, Schweitzer KS, Chun KT, Koegel C, Barbuch R, Bard M

Cloning and characterization of the Saccharomyces cerevisiae C-22 sterol desaturase gene, encoding a second cytochrome P-450 involved in ergosterol biosynthesis.

Gene 169:105-9 (1996)
DOI:10.1016/0378-1119(95)00770-9

[sce:YMR015C]

3  [PMID:16531502]

Morikawa T, Mizutani M, Aoki N, Watanabe B, Saga H, Saito S, Oikawa A, Suzuki H, Sakurai N, Shibata D, Wadano A, Sakata K, Ohta D.

Cytochrome P450 CYP710A encodes the sterol C-22 desaturase in Arabidopsis and tomato.

Plant Cell 18:1008-22 (2006)
DOI:10.1105/tpc.105.036012

[ath:AT2G34500 AT2G34490]