This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Enzymes, Subject name: Biochemistry
Inactive precursors of enzymes are known as: 
Select and explain. 
A. Apo enzymes, B. Coenzymes, C. Proenzymes, D. Holoenzymes
C: Proenzymes
Answer: C: Proenzymes 
Explanation: Ans. C. ProenzymesProenzymes or zymogens are inactive enzymes which undergo irreversible covalent activation by the breakdown of one or more peptide bonds. For example, Chymotrypsin, pepsinogen and plasminogen are proenzymes that are converted to active enzymes chymotrypsin, pepsin and plasmin respectively.