Question

Why does the enzyme pepsin (present in the stomach) denature in the intestine? A. The enzyme denatures due to change in temperature as it enters the intestine. B. The enzyme denatures due to the alkaline environment of the intestine. C. The enzyme denatures due to lack of substrate molecules in the intestine.

Answer 1

The enzyme denatures due to the alkaline environment in the intestine as enzyme pepsin works best in acidic ph

Answer 2

Your answer would be B. This is because pepsin has an optimum pH that is very low which is ideal for the acidic conditions of the stomach. However, as it enters a more alkaline environment (like the intestine) the ionisable side chains found in the active site of the enzyme start to donate protons (mainly the carboxylic acid groups from the amino acids that made up the enzyme). This alters the structure of the active site and prevents substrates from binding to it therefore 'denaturing' the enyzme.

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