EC Explorer

1.14.15.29

cholest-4-en-3-one 26-monooxygenase [(25S)-3-oxocholest-4-en-26-oate forming]

cholest-4-en-3-one + 6 reduced ferredoxin [iron-sulfur] cluster + 6 H⁺ + 3 O₂ = (25S)-3-oxocholest-4-en-26-oate + 6 oxidized ferredoxin [iron-sulfur] cluster + 4 H₂O (overall reaction);;(1a) cholest-4-en-3-one + 2 reduced ferredoxin [iron-sulfur] cluster + 2 H⁺ + O₂ = (25S)-26-hydroxycholest-4-en-3-one + 2 oxidized ferredoxin [iron-sulfur] cluster + H₂O;;(1b) (25S)-26-hydroxycholest-4-en-3-one + 2 reduced ferredoxin [iron-sulfur] cluster + 2 H⁺ + O₂ = (25S)-26-oxocholest-4-en-3-one + 2 oxidized ferredoxin [iron-sulfur] cluster + 2 H₂O;;(1c) (25S)-26-oxocholest-4-en-3-one + 2 reduced ferredoxin [iron-sulfur] cluster + 2 H⁺ + O₂ = (25S)-3-oxocholest-4-en-26-oate + 2 oxidized ferredoxin [iron-sulfur] cluster + H₂O;;

CYP125, CYP125A1, cholest-4-en-3-one 27-monooxygenase (misleading), cholest-4-en-3-one,NADH:oxygen oxidoreductase (26-hydroxylating), cholest-4-en-3-one 26-monooxygenase (ambiguous)

cholest-4-en-3-one,[reduced ferredoxin]:oxygen oxidoreductase [(25S)-3-oxocholest-4-en-26-oate-forming]

A cytochrome P-450 (heme-thiolate) protein found in several bacterial pathogens. The enzyme is involved in degradation of the host's cholesterol. It catalyses the hydroxylation of the C-26 carbon, followed by oxidation of the alcohol to the carboxylic acid via the aldehyde intermediate, initiating the degradation of the alkyl side-chain of cholesterol [4]. The products are exclusively in the (25S) configuration. The enzyme is part of a two-component system that also includes a ferredoxin reductase (most likely KshB, which also interacts with EC 1.14.15.30, 3-ketosteroid 9α-monooxygenase). The enzyme also accepts cholesterol as a substrate. cf. EC 1.14.15.28, cholest-4-en-3-one 27-monooxygenase.

created 2012 as EC 1.14.13.141, modified 2016, transferred 2018 to EC 1.14.15.29