competitive inhibitor

[113zami]

can someone please explain this sentence:

structurally, a competitive inhibitor resembles the transition state which the active site normally stabilizes.

thanks for the help

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[CannonD]

can someone please explain this sentence:

structurally, a competitive inhibitor resembles the transition state which the active site normally stabilizes.

thanks for the help

I think it means when a competitive inhibitor binds to the active site, the binding between the inhibitor and the active site cause their transition state become more stable which means they have the tendency to stay that way. for example in the active site there are positive and negative charge protein when the inhibitor enter the active site it neutralizes those charges. In other word it acts exactly as the substrate but it can't be converted into product.

 

[OMFS08]

can someone please explain this sentence:

structurally, a competitive inhibitor resembles the transition state which the active site normally stabilizes.

thanks for the help

Well to me I would say that the competitive inhibitor is fighting for a slot on the active site so with knowledge of the lock and key theory as well as the induced fit hypothesis, I would say the competitive inhibitor must have the same shape as the active site. So in the transition state the active site is stabilized by binding of some substrate so if the competitive inhibitor looks like that substrate then it can also bind to the active site and thus play a role in stability. Hope that helps. Just my 2 cents

 

[gkhan]

competitive inhibitors bind to the active site, causing a titration effect. so there is competition between the substrate and the enzyme and the inhibitor

non competitive bind to another region and deactivates the active site. there is no direct competition for the active site.

*posted same time as OMFS08
lock and key model is pretty much deemed null now a days. induced fit is where its at.

 

[Sama951]

Enzymes can bind substrates and release them in equilibrium, and every substrate turns into product via a transition state.

This transition state binds to the active site extremely tightly (you never get any dissociation of transition-state substrates from an enzyme)

So, a good competitive inhibitor will have similar structure to the transition state of the substrate, and therefore will bind REALLY well to the enzyme