Lock and key theory

• 'Lock and Key theory'


  A model to explain enzyme action
• Enzymes


  • Made of proteins
  • Biological catalysts substances that increase the rate of chemical reactions without being used up
• Active site of the enzyme


  The shape is specific for each substrate (substance the enzyme acts on)
• The lock is the active site on an enzyme
• The key is the substrate that fits into the active site
• When the substrate binds with the active site it forms an enzyme-substrate complex
• An enzyme can only act on one molecule at a time so this process happens very quickly