Enzymes

• Enzyme


  Protein that speeds up a chemical reaction
• Enzyme


  • Where the reaction occurs on the enzyme
  • Substance produced after the reaction
  • Speeds up reaction without being spent
• Active site


  Where the reaction occurs on the enzyme
• Substrate


  Substance that the enzyme acts on
• Product


  Substance produced after the reaction
• Catalyst


  Speeds up reaction without being spent
• Amylase


  Enzyme that breaks down starch
• Enzymes in digestion


  • Amylase (mouth, small intestine)
  • Protease (stomach, small intestine)
  • Lipase (small intestine)
• Buffer


  Keeps the pH constant
• Denaturation


  Active site charges shape and no longer complementary to substrate
• Properties of enzymes


  • Each enzyme only works with one type of substrate
  • Enzymes have an active site which only fits one type of molecule (substrate specific)
  • Enzymes work best at certain temperature and pH (optimum conditions)
• Enzyme


  Biological catalyst that speeds up a chemical reaction
• Enzyme structure and shape


  • Made of proteins
  • Have a very specific shape
  • Have a region called the active site
• Enzymes are substrate specific
• Lock and key theory


  Enzymes have an active site which only fits one type of molecule (substrate)
• Optimum conditions


  Enzymes work best at certain temperature and pH
• Denaturation


  If temperature or pH is too far from optimum, the enzyme's active site is permanently changed shape and it no longer works
• Effect of amylase enzyme on starch

  1. Starch is broken down into glucose

  2. Iodine turns blue/black in presence of starch, yellow/brown otherwise
• The blue/black colour fading proved amylase was breaking down the starch
• Independent variable


  Variable which is changed
• Dependent variable


  Variable which is measured
• Control variable


  Variable which is kept the same
• Independent variable = temperature

  Dependent variable = time taken for amylase to break down starch
• Kept same volume of amylase, starch, iodine added every 30 seconds to make it a fair test
• Could improve reliability by repeating experiment at each temperature and calculating average time
• Independent variable = pH values

  Dependent variable = time taken for amylase to break down starch
• Kept same volume of buffer, amylase, starch, iodine to make it a fair test
• Enzymes in digestion


  • Amylase (mouth, pancreas, small intestine - breaks down starch to glucose)

  Protease (stomach, pancreas, small intestine - breaks down proteins to amino acids)

  Lipase (small intestine - breaks down fats to fatty acids and glycerol)
• Each enzyme can only work on one type of molecule because the active site is specific in shape to that substrate
• Catalyst


  Speeds up rate of reaction without being used up
• Enzymes used in cheese making and biological washing powders


  • Rennet enzyme used in cheese making

  Enzymes in washing powders break down protein and fat stains
• Methods for creating stone-washed effect on jeans


  • Using pumice stones in washing machine (can damage fabric)

  Using amylase enzyme to break off small fiber ends on surface (loosens the fabric)

  Using cellulase enzyme to separate the cotton fibers (decreases pilling)
• Uses of enzymes in cosmetics industry


  • As antioxidants, moisturizing agents, whitening and other functional additives