This group represents cytochrome P450, CYP7A1 type. Gene cyp7a1 codes for the enzyme cholesterol 7-alpha-monooxygenase, which catalyses a rate-limiting step in cholesterol catabolism and bile acid biosynthesis by introducing a hydrophilic moiety at position 7 of cholesterol. This enzyme is important for cholesterol homeostasis []. Some of the enzymes belonging to this group are 7-alpha-hydroxycholest-4-en-3-one 12-alpha-hydroxylase, also involved in bile acid biosynthesis, and prostacyclin synthase, which catalyses the isomerization of prostaglandin H2 to prostacyclin (prostaglandin I2).
