So now that we've introduced Alice Derek Enzymes in this video, we're going to talk about how Alice Terek enzymes display Alice, Derek Kinetics. And so these Alice Derek Enzymes are actually pretty easy for biochemist to identify. And that's because Alice Derek Enzymes behave very, very differently. Then the McHale is meant in enzymes that we covered in our previous lesson videos. And so this includes responding differently to changes in substrate concentration as well as to the presence of inhibitors. And so it turns out that al hysteric enzymes most Alice Derek Enzymes display a sigmoid it'll curve or an s shaped curve on a kinetics plot instead of a rectangular hyperbole like McHale is meant in enzymes do. And so if we take a look at our image down below notice on the left enzyme kinetics spot, we're showing you a meticulous meant and ends on, and it's forming this same shape that we've seen so many times before in our previous lesson, videos referred to as a rectangular hyper below. Whereas if we take a look at the enzyme kinetics plot over here on the right, notice that we're showing an Alice Derek enzyme instead of um, Achilles meant an enzyme. And instead of showing a rectangular hyperba, it's showing this s shaped curve here, which is referred to as a sigmoid all curve. Now, recall that the Michaelis constant K M is the exact substrate concentration that allows for half of the V max. And so it turns out that the McHale is constant. Variable K m Onley applies to McHale is meant in enzymes. And so the substrate concentration that allows for half of the V max for Alice Terek enzymes is represented by the variable K 0.5. And so K 0.5 is pretty much the Alice Terek enzyme equivalent to the McHale is constant k m for them Achilles, mint and enzymes. And so, also on that note, the McHale is meant in equation. Onley applies for McHale is meant in enzymes, and the McHale is meant an equation does not apply for Alice Terek enzyme. So these air definitely some differences to take note about Alistair Eric Kinetics. And so this here concludes our introduction to Alistair Kinetics and will continue to learn Maura about Alistair Kinetics as we move forward in our course. So I'll see you guys in our next video
Which of the following statements regarding allosteric kinetics is false?
The rate of an allosteric enzyme reaction is dependent on substrate concentration [S].
The reaction velocity and substrate concentration always proportionally change in a Lineweaver-Burk plot.
At saturating [S], the kinetics of an allosteric enzyme will follow the Michaelis-Menten model.
Allosteric enzymes display second order kinetics leading to sigmoidal curvature on a kinetics plot.
None are false because all of the above are true.
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So another way for biochemist too pretty easily identify Alice Derek Enzymes is by plotting the enzyme kinetic data onto a line Weaver Burke plot. And that's because Alice Derek Enzyme kinetic data does not actually form a straight line on a line with Herbert plot, like the enzyme kinetic data of Nicholas Meant in Enzymes Do. And so notice down below. Over here, on the left hand side, we have a line Weaver Burke plot showing the enzyme kinetic data of, um, Achilles, meant in enzyme, and notice that the enzyme kinetic data of the McHale is meant an enzyme forms. Ah, straight line on the line Weaver Burke plot. And so here we can write in straight line. And so, of course, what this means is that the line Weaver Burke equation is going to apply for meticulous meant in enzymes. However, if we take a look at the line Weaver Burke plot over here on the right hand side notice it's showing the enzyme kinetic data of the Alice Terek enzyme and notice that the enzyme kinetic data of analysis Eric Enzyme plotted onto a line. Weaver Burke plot does not form a straight line, and so This, of course, means that the line we have Robert Equation does not apply to Alice Derek Enzymes. And again, it's pretty easy for biochemist to identify these Alice Derek Enzymes. When they plot the enzyme kinetic data onto the line, we revert plot. And so this here concludes our introduction to Alice Derek Enzyme Kinetics, and we'll be able to get a little bit of practice and our next video so I'll see you guys there.
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So another feature that Alice Terek enzymes display that Mikhail's meant in enzymes. Don't is this threshold effect. So let's explain this a bit further. So at very, very low substrate concentrations, it turns out that Michaela is meant in enzymes are actually mawr sensitive to changes in substrate concentration than Alice Derek Enzymes. And we can actually see that down below. In our enzyme kinetics plot, where this black curve here represents, the McHale is meant in enzymes. And the blue curve here represents Alice Terek enzymes. And so, uh, notice here were specifically focusing on low substrate concentration. So somewhere around this range, right here on the X axis. And so at these low substrate concentrations, notice that the Alice Terek enzyme pretty much doesn't even respond to changes in substrate concentration. Whereas the McHale is mention ends. I'm definitely does respond to changes and substrate concentration when it is low like this. And so that's exactly what we're mentioning up above in this line right here. Now it turns out that however eventually a threshold substrate concentration is going to be reached. And once this threshold substrate concentration is reached, this is where Alistair Eric Enzymes actually become mawr sensitive, much more sensitive to the changes and substrate concentration. And so notice down below in our plot here that the threshold substrate concentration is represented by this dotted blue line right here. And so notice that want this threshold substrate concentration is reached. The Alice Derek enzyme is much, much more sensitive to changes and substrate concentration. Now, ultimately, it This leads to the initial reaction velocity or the V not of the Alice Terek enzymes, uh, to approach the V max within a smaller and aim or narrow range of substrate concentration. And so we can also see that down below. And the ranges are represented by these bars that we have below the X axis here, the blue bar and the gray bar. The blue bar corresponds with the Alice Terek enzyme, and the gray bar here corresponds with the McHale is meant an enzyme. And so you can see that, uh, once we have, uh, the threshold substrate concentration reached. Um, the Alice Terek enzyme approaches V Max in a very, very narrow substrate. Concentration, however, for the McHale is meant in enzyme. It pretty much goes from zero all the way up to the max within a much, much wider range. And again, that's pretty much what we were saying up above and this line right here. And so all of this here actually creates what's known as the threshold effect. And so again, the threshold effect is something that Alistair IQ enzymes display that Nicholas mention enzymes don't and so, really, when it comes down to it, the threshold effect just says that below a certain substrate concentration. There's pretty much, very little to no Alice Derek enzyme activity. And so again, here's the threshold substrate, concentration and below the sub threshold substrate concentration. The Alice Derek enzyme has pretty much zero to know activity. But once the threshold substrate concentration has reached the al hysteric enzymes, activity gets turned on, and it can get up to V max pretty pretty quickly. And so, really, this threshold substrate concentration acts like an on and off switch for the Alice Derek enzyme, whereas for the meticulous meant in enzyme, it's pretty much always on as long as there's some substrate concentration. The McHale is meant an enzyme is always going to be on, and so you can see how this threshold effect feature of Alice Terek. Enzymes really gives Alice Terek enzymes another form of regulation that cells can use to regulate their metabolic pathways. And so this year concludes our introduction here to the threshold effect of Alice Derek Enzymes, and we'll be able to get a little bit of practice as we move forward in our course, so I'll see you guys in our next video.
Because of the _____________ substrate-binding-site(s) & conformation(s) on an allosteric enzyme, the range of [S] to reach the Vmax is _______________ for allosteric enzymes than it is for Michaelis-Menten enzymes.