Involved in the formation of secondary alcohols and ketones in stem cuticular wax. Catalyzes the hydroxylation of a methylene unit in the middle of alkane molecules to form secondary alcohols and possibly also a second hydroxylation leading to the corresponding ketones. A number of isoforms are produced. According to EST sequences. Expressed in the expanding regions of the inflorescence stems, specifically to the epidermal pavement cells, petioles and siliques. No visible phenotype under normal growth conditions, but stem wax of mutant plants are devoid of secondary alcohols and ketones and have increased alkane amounts. Belongs to the cytochrome P450 family.