Which of the following is the rate-limiting enzyme in pyrimidine synthesis?: (A) Aspoate transcarbamylase, (B) Dihydro-orotase, (C) Redvctase, (D) UMP kinase
Answer is A. Carbamoyl phosphate and aspaate combine to form carbamoyl aspaate is the rate-limiting step in pyrimidine synthesis. The enzyme is aspayl transcarbamoylase.