From the following list, correctly identify the reason (s) that might explain a decrease in Vmax due to a suboptimal pH during an enzyme assay.

a. Protonation of the substrate

b. Deprotonation of the amino acids in the enzyme's active site

c. Denaturation of the protein's tertiary structure

d. Decrease in the rate of substrate collisions with the enzyme's active site

e. Change in the entropy of the reaction

f. Increase in the molar extinction coefficient (e) of the product

The correct answer is -

a. Protonation of the substrate.

b. Deprotonation of the amino acids in the enzyme active site.

c. Change in tertiary structure in extreme conditions.

Explanation:

During an enzyme assay, suboptimal pH is changed and affect the Vmax to decrease and this could take place due to various reasons such as-

A) protonation of the substrate - Upon protonating or adding a proton or hydrogen cation to a substrate atom, the mass and the charge of the species each increase by one unit which make a conjugate acid.

B) Deprotonation of the amino acids in the enzyme's active site - Changing the pH will affect the charges on the amino acid molecules.

C) Denaturation of the protein's tertiary structure - Tertiary structure of the protein is basically a backbone of peptide chain with one or more secondary domains of proteins that increasing the pH or decreasing the pH get denature.

Thus, the correct answer is : option A, B, C.