Which of the following is the rate limiting enzyme of bile acid synthesis: (A) Mitochondrial 17 α hydroxylase, (B) Cytoplasmic 7 α hydroxylase, (C) Microsomal 7 α hydroxylase, (D) Mitochondrial 7 α hydroxylase.
Answer is C. Microsomal 7 α hydroxylase (cholesterol 7 α hydroxylase) is the rate limiting enzyme of bile acid synthesis. This enzyme is expressed only in liver.