This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Which of the following enzymes is involved in the urea cycle? 
Select and explain. 
A. Asparginase, B. Glutaminase, C. Argininosuccinate synthetase, D. Glutamate dehydrogenase
C: Argininosuccinate synthetase
Answer: C: Argininosuccinate synthetase 
Explanation: Argininosuccinate synthase links aspartate and citrulline via the amino group of aspartate and provides the second nitrogen of urea.