This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
Urea cycle components are all except 
Select and explain. 
A. Urease, B. Arginase, C. Transcarbamoylase, D. Arginosuccinase
A: Urease
Answer: A: Urease 
Explanation: l-Ornithine transcarbamoylase (EC 2.1.3.3) catalyzes transfer of the carbamoyl group of carbamoyl phosphate to ornithine, forming citrulline and ohophosphate. Argininosuccinate synthase (EC 6.3.4.5) links aspaate and citrulline the amino group of aspaate (reaction 3, Figure 28-16) and provides the second nitrogen of urea Hydrolytic cleavage of the guanidino group of arginine, catalyzed by liver arginase (EC 3.5.3.1), releases urea. Urease is not involved in the urea cycleRef: Harpers Illustrated Biochemistry, 30th edition, page no: 294