Effect of pH on Enzyme Activity

The tertiary structure of the active site of the enzyme is determined by hydrogen and ionic bonds between -NH₂ and -COOH groups and bonding and interactions between the R-groups.Each enzyme has an optimum pH.Since the pH is a measure of the hydrogen ion concentration, changes to the H⁺ concentration may alter the shape of the active site by:

• altering the charges on the amino acids that make up the active site
• breaking the hydrogen and ionic bonds that maintain the enzymes tertiary (3D) structure and causing the shape of the active site to change

Small changes in pH will reduce the enzymes activity.Large changes in pH will denature the enzyme.