A student of chemical engineering mistakenly engulfed the toxic compound "A" which was a potent inhibitor of a certain enzyme. He was immediately brought to a hospital where the doctor injected, intravenously, substrate "B" to minimize the toxic effect of Compound A. His life was saved from serious damage. The treatment method shows that compound A was a _ inhibitor.

Explanation

'Compound A' caused a toxic effect by inhibiting the action of a certain enzyme. 'Substrate B' was injected, which minimized the toxic effect of compound A, and this toxic effect was brought about by inhibiting the enzyme. The addition of a larger quantity of substrate allowed the enzyme to work to its normal capacity once again, as the inhibitory or toxic effect of compound A was minimized. Competitive reversible inhibitors compete with the substrate for the active site and if there is a greater amount of the substrate, the active site is more likely to bind to the substrate, rather than the inhibitor so, the activity of the enzyme is restored. This is the exact scenario described in the question, as the inhibitory effect was reversed upon addition of more substrate. Hence, the correct option is D.Option A, non-competitive inhibitors, decrease the Vmax of the enzyme so, addition of more substrate will not change or restore the enzyme's effectiveness.Option B, irreversible inhibitors, would have an effect that cannot be reversed under any circumstances so, addition of substrate would have no effect.Option C, temperature sensitive inhibitor has no relevance to the given scenario as temperature has not been mentioned as a factor in the question.