hey guys it's medical assistant is where medicine makes perfect sense thank you for watching my biochemistry playlist in previous videos we talked about enzyme kinetics we talked about Michaelis menten and Lynn Weaver Burke plots we talked about competitive Inhibitors alone non-competitive Inhibitors alone mixed Inhibitors and uncompetitive Inhibitors today let's compare among the four types of enzyme Inhibitors and let's get started please watch the videos in this playlist in order there are four types of enzyme Inhibitors as you know competitive non-competitive mixed and uncompetitive enzymes facilitate the reaction they are catalysts they increase the speed they lower the activation energy they are not changed by the reaction they do not change the equilibrium position they do not change the thermodynamics they do not alter your Delta G enzymes have two doors the front door and the back door the front is the active site the back door is the allosteric site the only inhibitor that binds the active site is competitive inhibitor every other inhibitor will bind to the allosteric site here is another difference competitive inhibitor is the only one that does not change your waymax which is the maximum rate of the reaction every other inhibitor will lower your Vmax recall that Vmax is directly proportional to the number of enzymes available and km is inversely proportional to the Affinity between the enzyme and the substrate competitive Inhibitors bind to the active site non-competitive Inhibitors bind to the allosteric site mixed Inhibitors allosteroxide uncompetitive Inhibitors allosteric site with competitive Inhibitors km will climb because we crush the Affinity can you overcome it yes we can overcome it and there is no change in Vmax with non-competitive Inhibitors km does not change V Max goes down let's understand competitive inhibit Cody the capitalist imagine that we had a store that sells 10 cars per day to 10 different customers then the competitive inhibitor Cody the capitalist open shop in front of the first one what's gonna happen to the attraction of customers to the old shop it will decrease so the Affinity will decrease and the km will go up but since Cody the capitalist did not alter the total number of units sold Vmax will stay the same so with competitive Inhibitors Cody the capitalist km will Climb by crushing the Affinity you can overcome it there is no change in Vmax next non-competitive Inhibitors Nancy the Karen you were driving your car you or the enzyme your core is the substrate down the road the speed limit was 15 but you went over the limit Nancy started yelling at you quote I'm gonna call the police on you close quote after hearing this what's going to happen to your speed it will decrease your speed V Max goes down but you still love your old piece of vintage Ford Model T car that needs to be cranked so there is no change in affinity and no change in km on Michaela's mint and graph if I want to draw a competitive inhibitor I will have to shift to the right like this but Vmax will not change if I want to draw non-competitive inhibitor my Vmax will have to decrease like this on the lenweaver beaver Burke plot competitive Inhibitors will have to shift me to the right did they change the Vmax no so I will intersect with the same point here because that's V Max or 1 over V Max to be specific but if I want to draw non-competitive Inhibitors Vmax will have to decrease which means 1 over V Max will have to increase but km should stay the same and it should look like this beautimus note that with competitive inhibitors the old line and the new line intersected on the y-axis but with non-competitive Inhibitors the old line and the new line intersected on the x-axis here is competitive Inhibitors and non-competitive Inhibitors pause and review and you absolutely need to memorize this competitive inhibitor is Cody the capitalist active site Affinity decreased because less customers went to the old store which means km went up however the total number of units sold did not change Vmax will stay the same Nancy the Karen delves through the back door when she yelled at you your speed decreased but you still love your car in the same manner mixed Inhibitors sometimes they bind to the enzyme alone in which case Affinity decreases because you're less likely to bind to the enzyme as a substrate nkm will go up or mixed Inhibitors might bind to the enzyme substrate complex all of them together after they have hugged each other which means the love bond between them is high and km is low so mixed inhibitor can bind this or this with different affinity for age which is what distinguishes mixed Inhibitors from non-competitive Inhibitors mixed Inhibitors like most Inhibitors bind the allosteric site and like most Inhibitors Vmax will decrease if I draw the old line and the new line I drew two lines because it could be this one or this one note that the old line and the no line intersected here or here whether you intersect here or here neither point is on either axis so with mixed Inhibitors we bind to the allosteric site km might increase and the Affinity will go down or km will decrease because the Affinity went up V Max will always go down let's add the uncompetitive inhibitor still binds the allosteric side km goes down because the Affinity goes up V Max goes down so the only inhibitor that decreases both the km and the Vmax is the uncompetitive inhibitor so here is is a cool way to remember it competitive Inhibitors are unique they are the only type of Inhibitors that bind to the active site every other inhibitor is going to bind to the allosteric site competitive Inhibitors are unique they are the only Inhibitors that do not change your Vmax every other inhibitor will lower your Vmax uncompetitive Inhibitors they only bind the enzyme substrate complex after they have hugged each other after they have hugged each other yeah and will lock them in place by preventing the Detachment all right we have already hugged each other and we will never detach so the hugging is very strong Affinity is high km is down this enzyme is not available to function anymore with any other substrates of emacs will drop V-Max will drop so 1 over V Max will go up and km will decrease so we will shift to the left again uncompetitive inhibitor is the only one that decreases both the km and the Vmax I decrease the Vmax I decrease the km so the two lines are parallel pause and review let's add something else what's the relationship between the old line the control line and after adding the no inhibitor let's see with competitive Inhibitors both will intersect at the y-axis with non-competitive Inhibitors both will intersect at the x-axis the way I remember it is that I imagine that Karen is threatening to slit my throat metaphorically speaking by doing this horizontal across the neck motion horizontal axis is the x-axis my students always recall my crazy mnemonics and they start laughing hysterically in the middle of the exam next with mixed Inhibitors both line will intersect at a point that's neither on the x-axis nor the y-axis with uncompetitive Inhibitors both line lines are parallel to one another let's draw a competitive inhibitor are you ready sure Cody the capitalist decrease the Affinity which means km goes up but did not change the number of units sold through the V Max did not change you just join these two lines together see that the old and the new line intersected on the vertical axis next non-competitive Inhibitors Nancy the Karen when she yelled at me I decreased my speed which means 1 over V Max will go up and then km did not change you just match these two points together note that the old line and the no line intersects on the horizontal axis as Karen threatens me horizontally with mixed Inhibitors Vmax will always decrease so 1 over V Max will always increase and then sometimes km goes up in which case we draw a line like this and sometimes km will decrease in which case we draw a line like this the old line and the new line will intersect at a point that's neither on the x-axis nor on the y-axis last uncompetitive Inhibitors the only inhibitor that decreases both the km and the Vmax let me decrease the V Max let me decrease the km and voila both lines are parallel oh medicosis biochemistry is so hard and nothing makes sense oh shut up medicine makes so much sense once you understand what the flip you're talking about if you want to be a good student bring a piece of paper and draw everything here from scratch without looking if you like this video if you love math and want more graphs check out my general pharmacology course tons of pharmacokinetics and for macrodynamics they are not that hard you can download this today at medicosisperfectness.com I also have a toxicology course medicosisperfectionalist.com thank you for watching Please Subscribe hit the bell and click on the join button you can support me 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