Catalyzes the C22-alpha-hydroxylation step in brassinosteroids biosynthesis (PubMed:9490746, PubMed:16460510). Converts campesterol (CR) to (22S)-22-hydroxycampesterol (22-OHCR, 22-hydroxyCR), campestanol (CN) to 6-deoxycathasterone (6-deoxoCT), and 6-oxocampestanol (6-oxoCN) to cathasterone (CT) (PubMed:9490746, PubMed:16460510). Can also use cholesterol and cholestanol as substrates (PubMed:9490746, PubMed:16460510). campesterol + O2 + reduced [NADPH--hemoprotein reductase] = (22S)-22-hydroxycampesterol + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] campestanol + O2 + reduced [NADPH--hemoprotein reductase] = 6-deoxycathasterone + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] cholesterol + O2 + reduced [NADPH--hemoprotein reductase] = (22S)-22-hydroxycholesterol + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] cholestanol + O2 + reduced [NADPH--hemoprotein reductase] = (22S)-22-hydroxycholestanol + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] 6-oxocampestanol + O2 + reduced [NADPH--hemoprotein reductase] = cathasterone + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] kcat is 1.8 min(-1) for campesterol (at pH 7.25 and 30 degrees Celsius) (PubMed:16460510). kcat is 0.049 min(-1) for campestanol (at pH 7.25 and 30 degrees Celsius) (PubMed:16460510). Plant hormone biosynthesis; brassinosteroid biosynthesis. Expressed in stems, leaves, shoots, and roots, with a higher expression in siliques and apical shoots. Belongs to the cytochrome P450 family.