Enzymes

• Enzymes


  Catalyst produced by living things
• Catalyst


  Substance that increases the speed of a reaction without being changed or used up in the reaction
• Enzymes


  • They are all large proteins
  • They are made of chains of amino acids
  • They have special shapes to catalyse reactions
• Enzyme catalyst


  1. Substrate binding

  2. Enzyme unchanged after reaction

  3. Products formed
• Active site


  Special site on the enzyme where the reaction takes place
• Catalyst


  A substance which increases the speed of a reaction, without being changed or used up in the reaction
• Enzymes are all large proteins which are made up of chains of amino acids
• Enzymes


  • These chains are folded into unique shapes, which enzymes need to do their jobs
• Chemical reactions


  Things either being split apart or joined together
• Active site


  Every enzyme has an active site with a unique shape that fits onto the substance involved in a reaction
• Enzymes


  • They usually only catalyse one specific reaction
  • For the enzyme to work, the substrate has to fit into its active site
• Lock and key model


  This is simpler than how enzymes actually work
• Induced fit model


  The active site changes shape a little as the substrate binds to it to get a tighter fit
• Changing the temperature


  Changes the rate of an enzyme-catalysed reaction
• A higher temperature increases the rate of an enzyme-catalysed reaction at first
• Denatured


  If it gets too hot, some of the bonds holding the enzyme together break, changing the shape of the enzyme's active site so the substrate won't fit any more
• Enzymes

  • They have an optimum temperature that they work best at
• If the pH is too high or too low


  It interferes with the bonds holding the enzyme together, changing the shape of the active site and denaturing the enzyme
• Enzymes


  • They have an optimum pH that they work best at
• Pepsin is an enzyme used to break down proteins in the stomach, it works best at pH 2