What kind of inhibition (uncompetitive, competitive, or irreversible) is present in each of the following:
c. The antibiotic deoxycycline inhibits the bacterial enzyme collagenase, slowing bacterial growth. Deoxycycline does not fit into the active site of collagenase and binds elsewhere on the enzyme.

Question

What kind of inhibition (uncompetitive, competitive, or irreversible) is present in each of the following:

c. The antibiotic deoxycycline inhibits the bacterial enzyme collagenase, slowing bacterial growth. Deoxycycline does not fit into the active site of collagenase and binds elsewhere on the enzyme.

Accepted Answer

All right. Hi, everyone. So this question is asking us to determine the kind of inhibition whether that's uncompetitive, competitive or irreversible present in the following. A certain pesticide works by attaching itself to an allosteric site on an insect digestive enzymes and slowing down their activity without permanently activating them. Now, option A says irreversible. Option B says uncompetitive option C says competitive and option D says cannot be determined. Now, first, it's important to recognize the major differences between these types of inhibition before analyzing the scenario specifically. Now, inhibition, if you recall means that the activity of the enzyme is in is decreased rather as a result of the inhibitor acting on the enzyme. So first, we have irreversible inhibition which if you recall is characterized by the formation of a covalent bond. So essentially the inhibitor is going to form a covalent bond to the active site of the enzyme. So this is going to be considered irreversible because the enzyme is completely shut down. It's not going to be able to bind to its substrate because you have the irreversible inhibitor, blocking it off, completely, blocking off the active side. Now, by contrast, uncompetitive and competitive inhibition are examples of of reversible inhibition. Rather, this is because at any point the inhibitor can detach itself from the enzyme. So here just to go ahead and differentiate between the types of reversible inhibition. Competitive inhibition is characterized by the inhibitor binding reversibly to the active site of the enzyme. So essentially the competitive inhibitor is going to compete with the substrate for the same spot on the enzyme. In other words, the active site. Now this is in contrast to uncompetitive inhibition, because an uncompetitive inhibition, the inhibitor binds to a non active site. It's not binding to the active site directly. It is binding to a different location to inhibit that enzymes activity. And so from here, we can go ahead and analyze the scenario given. So the first relevant piece of information that we come across when reading the scenario is that the inhibitor. In other words, the pesticide is going to bind to an allosteric site. That's important, right? Because what is an allosteric site recall that the allosteric site is simply a place where regulators can bind to an enzyme. An allosteric site is not the active site. So based on this information alone, we already have the answer to the question because only uncompetitive inhibitors bind to a place that is not the active site, irreversible and competitive inhibitors bind to the active site specifically. But just for the sake of going through this whole scenario here, the fact that the inhibitor itself doesn't permanently inactivate the enzyme just confirms our final answer because recall that only irreversible inhibition is permanently going to inactivate the enzyme. And so our answer just to clarify is option B the multiple choice, this is uncompetitive inhibition. And so with that being said, thank you very much for watching and I hope you found this helpful.

Verified video answer for a similar problem:

Key Concepts

Enzyme Inhibition

Competitive Inhibition

Allosteric Inhibition