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. Author manuscript; available in PMC: 2021 Jan 1.
Published in final edited form as: Adv Exp Med Biol. 2020;1268:257–283. doi: 10.1007/978-3-030-46227-7_13

Fig. 13.4.

Fig. 13.4

UVB-induced phototransformation of 7DHC, its hydroxyderivatives, and 7DHP to the corresponding secosteroidal, lumisterol, and tachysterol compounds

Shown is the metabolism of 7DHC by CYP11A1, the skin, and the subsequent transformations to the corresponding photoproducts after exposure to UVB. (?) – the enzyme transforming 7DHC to 20(OH)7DHC remains to be identified, since none of the products of 7DHC hydroxylation by CYP11A1 has its retention time. Because of the similarity of 20(OH)7DHC and 20-hydroxycholesterol, it is likely to be the same enzyme that transforms cholesterol into 20-hydroxychaolesterol, which is also detectable in the epidermis. (Reprinted from [208] with permission from Elsevier)