00:01
So before i get into this question, let's go over a line weaver brick plot really quickly.
00:09
So remember, this is a double reciprocal graph.
00:12
And the y -axis is a reciprocal of the speed of a reaction.
00:16
And the x -exis is a reciprocal of the substrate concentration needed in a reaction.
00:23
Km is the mckellon's constant.
00:26
It's a measure of the enzyme affinity for a substrate.
00:29
And this value for the graph can be thought of as the concentration of the substrate needed for a reaction to move forward.
00:41
The amount of substrate needed to reach one half of the maximum velocity of a reaction.
00:49
And vmax is the maximum velocity.
00:55
So what this means, the mckellen's constant increases if an enzyme bind, for reaction, i'll do that in red.
01:03
If this km value increases, then on the graph, you'd have a lower value because it's the reciprocal.
01:11
Same thing for vmax.
01:13
If vmax increases, again, i'll do red, you'd have a lower value on the graph because you're graphing the reciprocal.
01:21
If km decreases, do this in blue, you'll have a higher value on the graph because it's the reciprocal.
01:31
If vmax decreases, again in blue, same thing.
01:36
You'll have a higher value on the graph because it's a reciprocal.
01:41
Now, there's four main types of inhibition that people like to graph with this.
01:47
We'll start with the first one.
01:49
It's not non -competitive, it is competitive inhibition.
01:51
It's called competitive because the inhibitor binds to an active site on the enzyme.
01:57
So it's directly competing with the substrate.
02:00
Now, with competitive inhibition, because the enzyme's direct, or because the inhibitor is directly competing with the substrate, if you add more substrate, then you can still get the reaction to move forward at the same exact speed.
02:19
That also means you need more substrate to reach one half of the maximum velocity.
02:25
So, because you need more substrate, we're going to have a smaller value for km on this graph, but it's still going to have the same maximum velocity.
02:36
As a reaction without an inhibitor, because if you add that more substrate, you can get the reaction to go smoothly anyways.
02:46
With non -competitive inhibition, the inhibitor is not competing directly with the substrate...