A cytochrome P450 monooxygenase involved in the metabolism of retinoids and eicosanoids (PubMed:12711469, PubMed:21068195). In epidermis, may contribute to the oxidative metabolism of all-trans- retinoic acid. For this activity, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via cytochrome P450 reductase (NADPH--hemoprotein reductase) (PubMed:12711469). Additionally, displays peroxidase and isomerase activities toward various oxygenated eicosanoids such as prostaglandin H2 (PGH2) and hydroperoxyeicosatetraenoates (HPETEs) (PubMed:21068195). Independently of cytochrome P450 reductase, NADPH, and O2, catalyzes the breakdown of PGH2 to hydroxyheptadecatrienoic acid (HHT) and malondialdehyde (MDA), which is known to act as a mediator of DNA damage (PubMed:21068195). . This is the function of Ensembl gene identifier ENSG00000167600 (CYP2S1, cytochrome P450 family 2 subfamily S member 1).