Inhibitors

• Define enzyme inhibitors


  Substances that reduce the activity of an enzyme. It effects how the substrate binds to the enzyme; they therefore block/alter the shape of the active site
• Define a competitive inhibitor

  Binds to the active site so therefore can't bind. This forms an enzyme-inhibitor complex which catalytically inactive prevents enzyme-substrate complexes
• Effect of adding more substances in the pressence of competitive inhibitor

  Dilutes the effect of the inhibition. More substances it will be less likely that there will be collisions with inhibitors but more inhibitors means fewer enzyme-substrate complexes.
• Order of how a competitive inhibitor works

  Inhibitor enters enzyme environment, shape of inhibitor matches shape of the substrate, Due to kinetic energy all molecules moving, so sometimes inhibitor binds to enzyme active site prevent enzyme-substrate complex, Other active sites are available so reaction will occur at a lower rate.
• Define non-competitive inhibitor


  Inhibitors that bind somewhere other than the active site e.g. allosteric site
• How does a non-competitive inhibitor works

  Disrupts the teritary structure - changes the active site, active site will no longer be complementary to the substrate hence it can't bind and products can't form
• Order of non-competitive inhibitor

  Inhibitor enters environment, shape of inhibitor is different to shape of substrate, but it does however match the shape of a different part of the enzyme - the allosteric site, inhibitor binds which alters ative site. If inhibitor is reversible it can dissociate with the enzyme allowing enzymes to regain tertiary structure
• How do competitive inhibitors effect rate of reaction

  Reduces rate of reaction but not maximum velocity. If the substrate concentration increases maximum velocity can still be reached
• How do non competitive inhiitors effect rate of reaction

  Increasing substrate concentration won't overcome effect. This will decrease the rate of reaction as mre active sites are unavailable
• Define end-product inhibition


  Term used for a type of enzyme inhibition when the product of the reaction acts as an inhibitor to the enzyme that has produced it.