1.9 Enzyme Inhibition

1.9 Enzyme Inhibition

1. Competitive Inhibition

   • Bind to active site of enzyme - COMPETE against substrate
   • Inhibitors will have a similar shape to substrate
   • Block substrate from getting to active site by binding to enzymes active site
     • NO ENZYME-SUBSTRATE COMPLEXES formed
       • decreased rate of reaction
   • How much of enzyme inhibited depends on relative concentrations of inhibitor and substrate
     • Higher conc. of inhibitor = occupy most active sites
     • Higher conc. of substrate = chances of ENZYME-SUBSTRATE COMPLEXES increase
       • So increasing the conc. of substrate will increase rate of reaction (up to a point)

2. Non-Competitive Inhibition

   • Bind to Allosteric site - NOT COMPETING against substrate
   • Inhibitors can be completely different shape to substrate
   • Binding to the allosteric site causes the active site to change shape = substrate no longer fits so can't bind
     • NO ENZYME-SUBSTRATE COMPLEXES
   • Increasing substrate concentration has no effect on reaction rate

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