Complete the chart below.

Question

Chart comparing types of enzyme inhibition with Michaelis-Menten and Lineweaver-Burk plots.

Accepted Answer

Alright. So this practice problem just wants us to complete the chart down below, which is really just a chart of the reversible inhibitors that we covered in our previous lesson videos. And so this first row here wants us to determine the binding site for each of these reversible inhibitors. And so recall from our previous lesson videos that competitive enzyme inhibitors will compete with the substrate for a position in the enzyme's active site. So competitive inhibitors bind to the enzyme's active site, whereas all of these other reversible inhibitors will bind to some other allosteric site. And so, essentially what we can do is just, take this and, repeat this a few times here, because it is the allosteric site. And so, now we can move on to the next row, which is the Kilometers change. Now for competitive inhibitors, we know that the Kilometers, is going to be increased. And so, what we can say is that the kilometers is going to be increased with competitive inhibitors. Now for uncompetitive inhibitors, we focus on this u and the u reminds us of a u-turn, which means that everything's going to be going down, which means that both the kilometers is going to be decreased and, so is the v max is also going to be decreased. Now, moving on to mixed inhibitors, the, Kilometers of mixed inhibitors can actually, either increase or decrease. And so what we're gonna write here is that it actually depends for the k m. And so what it depends on is the values of alpha and alpha prime. So, recall that if alpha is greater than alpha prime, that's going to lead to an increase, which I'll just abbreviate with an I here, this represents an increase in the Kilometers, and then of course if the opposite is true, alpha is less than alpha prime, that's going to lead to a decrease and I'll abbreviate decrease with a d. And so moving on to noncompetitive inhibitors. Noncompetitive inhibitors have this no in it and so that reminds us that there's no change to the k m. So we'll say no change. So now moving on to the v max change of competitive inhibitors, recall that if the substrate can compete, then this, the enzyme can keep the same v max. And so with competitive inhibitors, because there is competition between the substrate and the competitive inhibitor, that means that, the v max, can be kept the same. And so, essentially what we'll say is that there is no change to the V max, with competitive inhibitors. We already determined that the V max of uncompetitive, in the presence of uncompetitive inhibitors is decreased. And so with mixed, and noncompetitive inhibitors, all of the V max change will be decreased. And so we can indicate a decreased V max for all of these. And so now that we filled out, essentially these first, three rows here, what we can do is utilize those 3 row rows to determine the change in the Michaelis Menten plot, as well as the change in the Lineweaver Burk plot. And so starting off with competitive inhibitors, we know that, ultimately, what's going to happen is, the v max is not going to be changed, which means that it's going to reach the same point up here by the end and, the kilometers is going to be increased. And so, essentially, it's going to look something like along the lines of this where the kilometers is now somewhere over here. So we can clearly see that there has been an increase to the kilometers and, notice that the v max is not changed. And so if we apply this to the line weaver Burk plot down below, if the black line here represents the uninhibited line, again, we know that the competitive inhibitor leads to an increase in the k m. And so, recall that the 0, marker on a line weaver Burkett plot acts as the infinity marker. And so if we wanna increase the kilometers, we need to move the x intercept closer to the 0 infinity marker. And so, essentially, what we're saying is that it's going to have a larger kilometers. But, again, there's no change to the v max, which means that it's going to cross the y, axis and have the same y intercept. And so this line right here would represent the competitive inhibitor. So, now moving on to uncompetitive inhibitor here, ultimately what we'll see is that there is a decrease to the Kilometers and a decrease to the V max. And so, ultimately, it's going to look something along the lines of this, where, you can see that the k m here is going to be somewhere about right here. So we're going to have a decreased k m, and again, the v max is also being decreased. And so, if we apply that to our Lineweaver Burk plot down below, again, the black line here represents the uninhibited line, and so a decreased Kilometers means that it's gonna get further away from the 0 infinity marker, and so the x intercept is gonna move further away. So we'll have a point right over here. And, of course, the v max is also going to decrease, which means it's going to get further away from the 0 infinity marker as well. And, it's going to be decreased proportionally. And really that is the key of uncompetitive inhibitors. So, again, we, remind ourselves of a u-turn, so you think, okay, well, this is just going to make a u-turn like this and it's going to create a parallel a parallel line. And so these two lines here are going to be parallel to each other. Now, moving on to mixed inhibition here, of course we know that there's going to be a decrease to the v max and, whether or not the k m actually increases or decreases depends on the values of these alpha and alpha prime. And so, if alpha is greater than alpha prime here in green, we know that there's going to be an increase to the kilometers and an increase to the kilometers means that the x intercept will be moved closer towards the 0 infinity marker. So it'll be a point over here. And of course, the v max is going to be decreased, which means it'll get further away from the 0 infinity marker. So, it'll look like this when, again, alpha is greater than alpha prime. And then, if we apply it when alpha is less than alpha prime, that's going to lead to a decrease in the Kilometers. So a decreased Kilometers is going to get further away from the 0 infinity marker. So it'll be somewhere over here. And then of course, the v max is still going to be decreased, so at the same point, and so here is our line right there. And so, the difference between, the parallel and this red line over here is that this line here does not necessarily have to be parallel. And so this would be exactly where alpha is less than alpha prime. Now, moving on to our last but not least type of reversible inhibitor, we have the non competitive inhibitor and of course, there's going to be no change to the Kilometers and so ultimately our curve is going to look something like this, where, the k m is going to remain exactly the same. And so, the v max is still going to be decreased, so you can see there is a decrease to the v max. And then, if we apply this to the Lineweaver Burk plot, again black line represents uninhibited line, no change to the Kilometers, which means that the x intercept is going to be exactly the same, but there is a decrease in the v max, which means that the y intercept's gonna get further away from the 0 infinity marker. So it'll be up here. And so, this would represent our un our non competitive, inhibited reaction. And so now, we've completed our entire table here and this table here is really, gonna be very helpful for review purposes. So, fill this table out, maybe about 2 or 3 times and, you guys should be good on these inhibitors. So, that concludes this video, and I'll see you guys in our next video.

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Complete the chart below.

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Recap of Reversible Inhibition practice set