Maltase is an enzyme that breaks down the disaccharide maltose into glucose molecules. The reaction usually takes place at a pH between 6 and 7. describe what would happen if the pH were decreased to 3?

Question

Maltase is an enzyme that breaks down the disaccharide maltose into glucose molecules. The reaction usually takes place at a pH between 6 and 7.  describe what would happen if the pH were decreased to 3?

anonymous · Answer

A change in pH would result in the destabilization of the enzyme structure and function, since enzymes are essentially proteins based structures, the change in pH would result in the disruption of bonding forces that are used to keep the enzyme together. These can include but not limited to hydrogen bonds, disulfide bridges, Van der Waals interactions etc. The reason for disruption is due to the increase in the concentration of H+ on amino acids making up the protein. 

Understand that each hydrogen atom on an amino acid possess a different acid dissociation constant (pKa), since an enzyme can have up to thousands of amino acids, the functional pH range is an average number in which the enzyme can react efficiently. This corresponds to the lowest energy state in which the charges on the amino acids and hydrogen bond formation are optimized to form the enzyme structure . 

For Maltase this optimal structure is maintained between pH 6 to 7 neutral (like most enzymes). A decrease in the pH environment would increase the concentration of H+,  promoting the protonation of amino acids causing a disruption in hydrogen bonding (O....H). Thus ultimately disrupting the enzyme and decreasing its reaction efficiency.

You can see the effect of pH on amino acids by knowing their pKa and using the Henderson Hasslebach equation $$pH = pKa - \log_{}([A-]/[HA])  $$