Question

The optimal pH for the action of pepsin is

• A. 1.8
• B. 6.8
• C. 7
• D. 7.8

Answer 1

The correct option is A 1.8

The optimal pH for the action of the proteolytic enzyme pepsin is 1.8. Pepsin is produced by the action of hydrochloric acid on pepsinogen, a constituent of the gastric juice secretion.
The hydrochloric acid keeps the pH of the gastric juice as low as 1.8, so that pepsin can catalyse the digestion of proteins efficiently.
6.8 is the optimum pH for salivary amylase, and 7.8 is the optimum pH for the actions of the enzymes in the small intestine.