Amino Acid & Protein Metabolism · NEET PG Preparation Biochemistry
During the urea cycle, which of the following molecules acts as an essential allosteric activator of carbamoyl phosphate synthetase I (CPS I)?
Practice question from Amino Acid & Protein Metabolism (NEET PG Preparation Biochemistry), with the correct answer and a step-by-step solution.
medium · MCQ · Q-68CE79
During the urea cycle, which of the following molecules acts as an essential allosteric activator of carbamoyl phosphate synthetase I (CPS I)?
- A.Ornithine
- B.Citrulline
- C.N-AcetylglutamateCorrect answer
- D.Argininosuccinate
Solution
N-Acetylglutamate (NAG) is an obligatory allosteric activator for carbamoyl phosphate synthetase I (CPS I), the rate-limiting enzyme of the urea cycle. NAG is synthesized from acetyl-CoA and glutamate by the enzyme N-acetylglutamate synthase, whose activity is stimulated by arginine.
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