What is the consequence of histidine 57 acting as an acid during the removal of the leaving group in the acylation phase?

• A. It increases the nucleophilicity of serine 195.
• B. It accepts a proton to stabilize the tetrahedral intermediate.
• C. It donates a proton to facilitate the cleavage of the peptide bond.
• D. It forms a covalent bond with the substrate.

Answer: (C)