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competitive inhibitor

Discussion in 'DAT Discussions' started by 113zami, Jun 4, 2008.

  1. 113zami

    113zami 2+ Year Member

    Oct 4, 2007
    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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  3. CannonD

    CannonD 2+ Year Member

    Jan 15, 2008
    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.
  4. OMFS08

    OMFS08 Tooth Extractornator 7+ Year Member

    May 11, 2008
    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
  5. gkhan

    gkhan 2+ Year Member

    May 27, 2008
    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.
  6. Sama951

    Sama951 2+ Year Member

    Apr 14, 2008
    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

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