Biochemistry General a6feae5a Control of urea cycle involves the enzyme: A Carbamoyl phosphate synthetase B Ornithine transcarbamoylase C Argininosuccinase D Arginase High-Yield Explanation CPS-I reaction is the rate-limiting step in urea formation. It is irreversible and allosterically regulated. Reference: Vasudevan 7th ed, pg 203