Question

Which of the following statements is incorrect regarding enzymatic activity?

• A. It increases with increase in substrate concentration upto the saturation point.
• B. It is highest at optimum pH value.
• C. It initially decreases with increase in pH value.
• D. It initially increases with increase in temperature and then decreases.

Answer 1

The correct option is C It initially decreases with increase in pH value.

Every enzyme possesses an optimum pH value where it is most effective. Most enzymes show maximum activity in a pH rage have their optimum pH in the acidic or alkaline range. E.g., pepsin of gastric juice has its optimum at pH 2 (acidic) whereas trypsin of pancreatic juice shows maximum activity by at pH 8.8 (alkaline). A rise and fall in pH reduces enzyme activity by changing the degree of ionisation of its side chain.

So, the correct answer is 'It initially decreases with increase in pH value'.