Enzymes

• Enzymes


  Catalysts produced by living things that speed up chemical reactions
• Chemical reactions are what make you work, and enzymes are what make them work
• Enzymes


  • Living things have thousands of different chemical reactions going on inside them all the time
  • Enzymes reduce the need for high temperatures and only speed up the useful chemical reactions in the body
• Catalyst


  A substance which increases the speed of a reaction, without being changed or used up in the reaction
• Enzymes


  • They are all large proteins made up of chains of amino acids folded into unique shapes
  • Enzymes have an active site with a unique shape that fits onto the substance involved in a reaction
  • Enzymes usually only catalyse one specific reaction
• Active site


  The part of the enzyme where the substrate binds
• Substrate


  The substance that an enzyme acts on
• Induced fit model


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


  The rate of an enzyme-catalysed reaction increases at first
• If temperature gets too high

  Bonds holding the enzyme together break, changing the shape of the active site, so the substrate won't fit anymore (enzyme is denatured)
• Enzymes


  • They have an optimum temperature where they work best
  • They also have an optimum pH where they work best
• Pepsin is an enzyme used to break down proteins in the stomach, and it works best at pH 2 (acidic conditions)