Question

An example of feedback inhibition is

• A. Allosteric inhibition of hexokinase by glucose 6-phosphate
• B. Cyanide action on cytochrome
• C. Sulpha drug on folic acid synthesis in bacteria
• D. Reaction between succinic dehydrogenase and succinic acid

Answer 1

Answer: (A)

Allosteric inhibition of hexokinase by glucose 6-phosphate

Feedback inhibition is the process by where the end product terminates the reaction. The accumulation of the end product interferes with the enzymatic activity by changing the shape of its active site. On changing the shape of the active site, the substrate does not attach to the active site and thus the reaction terminates. During glycolysis, the glucose changes to glucose 6 phosphates in presence of hexokinase. When the amount of glucose 6 phosphate exceeds it deactivate hexokinase.

So, the correct answer is option A.