Enzymes

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  • Created by: emma
  • Created on: 17-03-14 22:10
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  • Enzymes
    • What are they?
      • Biological catalysts
        • Don't get used up in reaction
        • Lower activation energy  (minimum amount of energy required for a chemical reaction)
      • Protein
        • Specific 3D shape that have specifically complementary active site to substrate
          • Forming enzyme substrate complex
    • Lock and Key
      • Substrate enters enzyme active site
        • Substrate fits exactly into active site
          • Products formed no longer fit into active site
            • Enzyme free to take part in another reaction
    • Induced Fit
      • Substrate enters enzyme active site
        • Binding substrate induces the change in the shape of the active site
          • When substrate leave active site returns to normal shape
    • Effect of temperature
      • Temp increases up to optimum enzymes have more kinetic energy
        • More likely to collide and react with substrate
          • More enzyme substrate complexes formed
      • Above optimum enzyme vibrates more so weaker hydrogen bonds break
        • shape of active site is changed
          • No more enzyme substrate complexes
    • PH alter from optimum
      • Ionic bonds in tertiary structure broken
        • Changes shape in active site
          • No more enzyme substrate complexes
    • Substrate concentration
      • Low SC not all active sites are full
        • Substrate is limiting factor
      • SC increases rate of reaction increases
        • Substrate no longer limiting factor
      • After saturation point SC increases but there are no more enzyme active sites
        • Rate of reaction levels off
          • Enzyme concentration is the limiting factor
    • Inhibitors
      • Competitive
        • Similar structure to substrate
          • Binds to active site
            • Prevents normal substrate from binding
              • Fewer enzyme substrate complexes
    • Non competitive
      • Not similar structure to substrate
        • Binds away from active site
          • Alters shape of active site
            • Fewer enzyme substrate complexes

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