Human 25-Hydroxycholesterol 7-alpha-hydroxylase, CYP7B1 ELI

A cytochrome P450 monooxygenase involved in neural cholesterol clearance through bile acid synthesis (PubMed: 25201972, PubMed: 10748047).

Catalyzes 7-alpha hydroxylation of (24S)-hydroxycholesterol, a neural oxysterol that is metabolized to bile acids in the liver (PubMed: 25201972, PubMed: 10748047).

Mechanistically, 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 (CPR; NADPH-ferrihemoprotein reductase) (PubMed: 25201972, PubMed: 10748047).