Question

QUESTION 7 Salivary amylase acts in the mouth where the pH is -7 but it becomes inactivated in the stomach after a meal where the pH is -1. Why does a decrease in pH from about pH 7 to pH 1 result in the salivary amylase protein becoming inactive? O lonisable amino acid side chains of the salivary amylase protein will be protonated, thereby disrupting the normal intra-protein hydrogen bonds, resulting in unfolding (denaturing) of the salivary amylase protein. The covalent disulphide bonds are disrupted by the low pH, resulting in the two polypeptides making up salivary amylase separate away from each other. lonisable amino acid side chains of the salivary amylase protein will be deprotonated, thereby disrupting the normal intra-protein hydrogen bonds, resulting in unfolding (denaturing) of the salivary amylase protein. New covalent disulphide bonds form due to ionisation changes within the salivary amylase protein, resulting in an o abnormally tightly folded structure.