A cytochrome P450 (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) conformation. 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 9¦Á-monooxygenase). The enzyme also accepts cholesterol as a substrate. cf. EC 1.14.15.28, cholest-4-en-3-one 27-monooxygenase.
![Example Structure of cholest-4-en-3-one 26-monooxygenase [(25S)-3-oxocholest-4-en-26-oate forming] EC#: 1.14.15.29](/wp-content/uploads/enzyme-structure/1.14.15.29.jpg)