Involved in the utilization of cholesterol as the sole carbon and energy source by degrading the side chain during infection (PubMed:20843794). Primarily catalyzes the sequential oxidation of the terminal methyl of cholest-4-en-3-one into (25R)-26-hydroxycholest-4-en-3-one (alcohol), (25R)-26-oxocholest-4-en-3-one (aldehyde), to finally yield the carboxylic acid (25R)-3-oxocholest-4-en-26-oate (PubMed:20843794, PubMed:20889498). In vitro, Cyp142 catalyzes with equal preference the oxidation of both (25R)- and (25S)-26-hydroxycholest-4-en-3-one diastereomers to the corresponding carboxylic acid which is a prerequisite for entry into the beta-oxidation pathway (PubMed:20843794). Also able to sequentially oxidize cholesterol itself, not only cholest-4-en-3-one (PubMed:20843794). cholest-4-en-3-one + 5 H(+) + 3 O2 + 6 reduced [2Fe-2S]-[ferredoxin] = (25R)-3-oxocholest-4-en-26-oate + 4 H2O + 6 oxidized [2Fe-2S]-[ferredoxin] cholest-4-en-3-one + 2 H(+) + O2 + 2 reduced [2Fe-2S]-[ferredoxin] = (25R)-3-oxocholest-4-en-26-ol + H2O + 2 oxidized [2Fe-2S]-[ferredoxin] (25R)-3-oxocholest-4-en-26-ol + 2 H(+) + O2 + 2 reduced [2Fe-2S]-[ferredoxin] = (25R)-3-oxocholest-4-en-26-al + 2 H2O + 2 oxidized [2Fe-2S]-[ferredoxin] (25R)-3-oxocholest-4-en-26-al + H(+) + O2 + 2 reduced [2Fe-2S]-[ferredoxin] = (25R)-3-oxocholest-4-en-26-oate + H2O + 2 oxidized [2Fe-2S]-[ferredoxin] cholesterol + H(+) + NADPH + O2 = 26-hydroxycholesterol + H2O + NADP(+) 26-hydroxycholesterol + 2 H(+) + O2 + 2 reduced [2Fe-2S]-[ferredoxin] = (3beta)-hydroxy-cholest-5-en-26-al + 2 H2O + 2 oxidized [2Fe-2S]-[ferredoxin] (3beta)-hydroxy-cholest-5-en-26-al + NADPH + O2 = (3beta)-hydroxy-cholest-5-en-26-oate + H2O + NADP(+) (25S)-3-oxocholest-4-en-26-ol + 2 H(+) + O2 + 2 reduced [2Fe-2S]-[ferredoxin] = (25S)-3-oxocholest-4-en-26-al + 2 H2O + 2 oxidized [2Fe-2S]-[ferredoxin] (25S)-3-oxocholest-4-en-26-al + H(+) + O2 + 2 reduced [2Fe-2S]-[ferredoxin] = (25S)-3-oxocholest-4-en-26-oate + H2O + 2 oxidized [2Fe-2S]-[ferredoxin] Inhibited by econazole, clotrimazole and miconazole. kcat is 84 min(-1) for cholest-4-en-3-one as substrate (PubMed:20843794). kcat is 16.7 min(-1) for cholesterol as substrate (PubMed:20843794). kcat is 0.0062 min(-1) for cholest-4-en-3-one as substrate (PubMed:20889498). Steroid metabolism; cholesterol degradation. By cholesterol. Belongs to the cytochrome P450 family.