Question

Why does the enzyme pepsin (present in the stomach) denature in the intestine?

The enzyme denatures due to change in temperature as it enters the intestine.
The enzyme denatures due to the alkaline environment of the intestine.
The enzyme denatures due to lack of substrate molecules in the intestine.

Answer 1

Pepsin needs a highly acidic medium to work and that is why the stomach releases hydrochloric acid before pepsin is released to work. Pepsin is therefore denatured in the intestine due to the alkaline environment of the intestine.