Indicate whether each of the following describes a competitive or a noncompetitive inhibitor.
e. Adding more substrate to the reaction restores the enzyme activity.

Question

Indicate whether each of the following describes a competitive or a noncompetitive inhibitor.

e. Adding more substrate to the reaction restores the enzyme activity.

Accepted Answer

All right. Hello everyone. So this question is asking us to determine which of the following inhibitors restores the activity of the enzyme by adding more substrate available to the reaction. Option A says noncompetitive inhibitors B says competitive inhibitors C says irreversible inhibitors and D says none of those so very quickly, right? I just want to go over the types of inhibition described here in the question and then talk about not only what they mean but also how to potentially circumvent them, right? Or restore the activity of the enzyme. So let's start off with noncompetitive inhibition for option A here. Well, first of all, what is noncompetitive inhibition? Well, a noncompetitive inhibitor, if you recall is one that's binding to an allosteric site on the enzyme. So the active site is on the enzyme is the place on the enzyme where the reaction is taking place. But the allosteric site is where regulators like inhibitors can bind to change the enzyme's activity. So when it comes to the context of the question, will noncompetitive inhibition be overcome by increasing the activity of the enzyme. And the answer is no right. The reason for this is because the noncompetitive inhibitor doesn't actually compete with the substrate of that particular enzyme. So just to go ahead and summarize once more, a noncompetitive inhibitor is going to change the shape of the enzyme and therefore the activity but increasing the concentration of the substrate won't change the inhibition. And that's because a noncompetitive inhibitor doesn't compete with the substrate for the active site of the enzyme. So A is not going to be correct. Now, b on the other hand, competitive inhibition refers to an inhibitor that is binding to the active site of the enzyme in question. And so here, the reason why it's described as competitive inhibition is because the inhibitor is competiting, not competiting. Sorry, competing. There we go. The inhibitor is competing with the substrate of the enzyme for the available active site. So in this context, increasing the concentration of the substrate will in fact restore the activity of the enzyme because it's almost as if increasing the concentration of the substrate will quote unquote, overpower the amount of the inhibitor that's available in solution. So basically, if you increase the concentration of the substrate relative to the inhibitor, because they're competing for the same active site, then it's more likely that the substrate will bind to the active site and not the inhibitor itself. So just for the sake of completeness, let's talk about irreversible inhibition. Well, irreversible inhibition as the name implies involves the inhibitor forming a covalent bond with the enzyme So because the bond between inhibitor and the enzyme is covalent, it rather the enzyme is going to be permanently inactivated. So if it's already been inactivated by this Covid lid bomb that's forming, then adding more of the substrate won't overcome this irreversible inhibition. So C is not correct either and neither is D right. So our correct answer is going to be option B in the multiple choice because competitive inhibitors will be overpowered, so to speak, by adding more of the substrate and there you have it. So with that being said, thank you so very much for watching and I hope you found this helpful.

Indicate whether each of the following describes a competitive or a noncompetitive inhibitor.
e. Adding more substrate to the reaction restores the enzyme activity.

Verified video answer for a similar problem:

Key Concepts

Competitive Inhibition

Noncompetitive Inhibition

Enzyme Activity

Indicate whether each of the following describes a competitive or a noncompetitive inhibitor.e. Adding more substrate to the reaction restores the enzyme activity.

Verified video answer for a similar problem:

Key Concepts

Competitive Inhibition

Noncompetitive Inhibition

Enzyme Activity

Indicate whether each of the following describes a competitive or a noncompetitive inhibitor.
e. Adding more substrate to the reaction restores the enzyme activity.