27-hydroxycholesterol is 7alpha-hydroxylated 27-hydroxycholesterol + NADPH + H+ + O2 => cholest-5-ene-3beta,7alpha,27-triol + H2O + NADP+ 27-hydroxycholesterol, NADPH + H+, and O2 react to form cholest-5-ene-3beta,7alpha,27-triol, H2O, and NADP+. This reaction is catalyzed by CYP7B1 in the endoplasmic reticulum membrane. Defects in CYB7B1 are associated with failure of 7alpha-hydroxylation in vivo, and with liver damage, confirming both the function of the enzyme and the central role of the liver in this metabolic process (Setchell et al. 1998). Authored: Jassal, B, 2007-01-19 10:34:59 Edited: D'Eustachio, P, 2007-04-30 14:43:26 Pubmed10588945 Pubmed9802883 Reactome Database ID Release 43191972 Reactome, http://www.reactome.org ReactomeREACT_9994 Reviewed: D'Eustachio, P, 2007-04-30 14:43:26