This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mechanisms of Enzyme Action, Subject name: Biochemistry
Chymotrypsinogen is a 
Select and explain. 
A. Zymogen, B. Carboxypeptidase, C. Transaminase, D. Elastase
A: Zymogen
Answer: A: Zymogen 
Explanation: Ans. is 'a' i.e. Zymogen * Proteolytic digestive enzymes known as proteases have two main classes depending on specificity for the amino acids forming the peptide bond to be hydrolysed.