3. Enzymes work best at optimal temperature and pH values. For example, the enzyme, pepsin, in your stomach must be able to function in a highly acidic environment to break peptide bonds found in proteins. Acidic or basic conditions can disrupt the hydrogen bonds between the loops of the protein chains. If this disruption occurs near the active site, the enzyme can become distorted and not fit the substrate perfectly. The rate of reaction is reduced as more enzymes become denatured. a) What is the optimal pH for pepsin