Which enzyme acts on proteins?

• A. Protease enzyme
• B. Enzyme
• C. Substrate
• D. Optimum

Answer: (A)

Proteins are broken down by a specific type of enzyme called a protease. Proteases catalyze the hydrolysis of peptide bonds in proteins, turning them into smaller peptides or amino acids. So, when the question asks which enzyme acts on proteins, the best answer is the protease enzyme because it is specialized to target and cleave proteins.

The other options don’t fit as well: an enzyme is any biological catalyst, not necessarily one that acts on proteins; a substrate is what an enzyme acts on (the protein, in this case, would be the substrate of a protease), and “optimum” refers to the conditions (like temperature or pH) where an enzyme works best, not to a type of enzyme.