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Main content
Current time:0:00Total duration:4:55
AP.BIO:
ENE‑1 (EU)
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ENE‑1.G (LO)
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ENE‑1.G.4 (EK)

Video transcript

in the video on competitive inhibition we saw that competitive inhibition is all about a substrate or potential substrate and inhibitor competing for the enzyme and whoever gets there first gets the enzyme if the inhabitant if the inhibitor gets there first then the substrate isn't able to bind and of course no reaction is catalysed if the substrate is able to get there first then the inhibitor isn't able to bind and the reaction does get catalyzed now the inhibitor and the substrate they mount both might compete for the active site if we're talking about competitive inhibition but you also have allosteric competitive inhibition where they're still trying to compete for the enzyme whoever gets there first gets the enzyme but the inhibitor doesn't necessarily bind at the active site they bind at an allosteric site but it's the same idea if the inhibitor gets to the allosteric site before the substrate gets to the active site then the conformation of the protein changes so that the active site you know changes a little bit something like let me draw in that same color it changes the conformation of the protein changes a little bit and then the actual the actual intended substrate isn't able to bind if the intended substrate binds then that changes the conformation a little bit at the allosteric site and then the inhibitor isn't able to bind so if that's competitive inhibition where there's like who do I get who gets to the enzyme first what is non-competitive inhibition all about well let's let's draw that so non-competitive inhibition so non-competitive competitive inhibition and the big picture here is that they can both bind whether one binds to the enzyme doesn't affect whether the other binds so let's talk about it a little bit so this is my enzyme that's my enzyme right over there and what we have happening of course is if the substrate is able to get to the active site then of course the reaction is going to be catalyzed and we saw that we saw that up here substrate substrate bonding binds to the active site and then the reaction is catalyzed in this case the substrate got broke up into two other molecules but a non-competitive inhibition what happens is the substrate combined and so can an inhibitor and so can inhibitor and the inhibitor combined in an allosteric site so this is our inhibitor right over here the inhibitor can bind at an allosteric site and when they're both mild knows they're not they're not competing for the enzyme they both can be on the enzyme this can this character can bind to the enzyme whether or not the substrate is there but if this guy binds to the enzyme the substrate can still bind to the enzyme but now the reaction isn't going to proceed so now the reaction is going to look like this let me so now there's no book there's not going to be in a reaction if this happens the only the only option is is that they both unbind so now this character is just going to leave the active site no reaction no reaction has been catalyzed so it just prevented anything from happening and maybe this guy this guy leaves as well and the way I showed this non-competitive inhibition I showed it happening at an allosteric site didn't have the inhibitor attaching at an allosteric site but it actually doesn't even have to be the same case as long as it does not prevent the as long as it can actually bind close to or even at the active site as long as it does not prevent the substrate from binding to the active site so you can even have a situation like this so you can even have a situation like this this is the one that's typically given for non-competitive inhibition where you have the inhibitor binding in an allosteric site but the idea here is that they're not competing both of them combined to the the enzyme if one of them binds first then the other one can still bind if if the if the substrate binds first then the inhibitor can still bind if the inhibitor binds first and the substrate can still bind but if the cat the reaction is not going to be is not going to be catalyzed but you can even have a situation you can even have a situation where the inhibitor and the substrate can both bind in or around the active site so that's the inhibitor and then this is our substrate this is substrate but once again this reaction is not going to occur we have non-competitive inhibition they're not competing for the thing they can both bind to it whether they combined isn't dependent on whether the other one is bound but if the inhibitor is there then it's kind of it's not it's not going to allow the reaction to actually be catalyzed as opposed to competitive inhibition whoever gets to the enzyme first gets the enzyme hopefully that clarifies things
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