EC Explorer

1.14.15.28

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

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

CYP142

cholest-4-en-3-one,reduced [2Fe-2S] ferredoxin:oxygen oxidoreductase [(25R)-3-oxocholest-4-en-26-oate-forming]

This cytochrome P-450 (heme-thiolate) enzyme, found in several bacterial pathogens, is involved in degradation of the host 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. The products are exclusively in the (25R) conformation. The enzyme also accepts cholesterol as a substrate. cf. EC 1.14.15.29, cholest-4-en-3-one 26-monooxygenase [(25S)-3-oxocholest-4-en-26-oate forming]. The enzyme can receive electrons from ferredoxin reductase in vitro, its natural electron donor is not known yet.

created 2016 as EC 1.14.13.221, transferred 2018 to EC 1.14.15.28