Thread:Cholesterol to 7 dehydrocholesterol (1)
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Could someone please help me (clinician). Is there a pathway from Cholesterol back to 7 dehydrocholesterol in man? Some lecture books in chemistry seem to suggest so but I can't find this in the literature.
Hi SuEs. Well, the enzyme that performs the forward reaction, DHCR7, is technically capable of preforming the reverse reaction (http://enzyme.expasy.org/EC/1.3.1.21), but not under physiological conditions where [NADPH] out numbers [NADP+] by at least 100:1 (http://www.biochemj.org/content/115/4/609). There is literature on the downregulation of DHCR7 in response to high levels of cholesterol, leading to increased vitamin D production (http://www.jbc.org/content/291/16/8363.full.pdf), but I also can't find anything about biological reactions that convert cholesterol back into 7DHC. AlexanderPico 22:34, 25 May 2017 (UTC)
