Enzymes

• Catalyst


  • An agent that is added to a chemical reaction to increase the rate of reaction
  • They reduce the activation energy of the reactants to create products
  • A catalyst is NOT used up at the end of the reaction and can be recycled
• Enzyme


  • Proteins (made of chained amino acids) created by ribosomes, that speed up many biological processes from years to seconds.
• Anabolic Enzymes

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  Builds up substrate
• How enzymes work

  
  

  Enzymes are highly specific – only one enzyme for type of substrate. Only the correct substrate can bind to the correct enzyme

  • Substrate will bind to the activation site of the enzyme
  • Called an induced fit – won't start a reaction unless correct substrate is bound
• Enzyme regulation

  • Enzymes are fragile, and must be kept in their preferred environment otherwise they metaphorically pack up and leave (stop working)
  • Any damage or blocking of the activation site prevents substrate from binding to the enzyme
  • 2 main factors to regulate: temperature & pH
• Temperature


  • If the temperature exceeds what an enzyme will function in, the bonds will break, denaturing (lose its shape) the enzyme - this is irreversible damage
  • If it drops below the temperature, the collision rate of substrate hitting enzyme will decrease (collision theory), decreasing the rate of reaction
• pH


  • pH refers to the amount of H+ ions within a solution
  • Each enzyme has a preferred pH it likes to operate in for maximum efficiency
  • Too far either side, denatured
• Concentration of substrate to enzyme

  • More substrate = more reaction
  • But there is a limit to how much substrate, at a certain point, all active sites will be occupied
  • Enzymes can be considered a limiting reagent (where quantity of this reagent is influencing the rate of reaction)
• Enzymes


  • Each enzyme has a preferred pH it likes to operate in for maximum efficiency
  • Too far either side, denatured
• Enzymes that like acidic/basic solutions

  • Pepsin in your stomach (acidic)
  • Trypsin in the small intestines (basic)
• H+ and OH-


  Ions that determine pH
• Limiting reagent


  Where quantity of this reagent is influencing the rate of reaction
• Catabolic enzymes

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  Break down substrates