enzymes

• enzymes:

  • biological catalysts
  • made out of protein
  • break up and join molecules
  • each has its own uniquely shaped active site where the substrate binds
• key and lock relationship:

  • shape of the substrate is complementary to the shape of the active site
  • forms an enzyme-substrate complex
  • once bound, the reaction takes place and the products are released from the surface of the enzyme
• optimum temperature:

  • around 37.5 degrees
  • rate of reaction increases with an increase in temperature until optimum
  • after that the rate of reaction rapidly decreases and the active site changes in shape - enzyme denatures
• optimum pH:

  • if pH is too high or low active site changes - enzyme denatures
  • most enzymes' optimum pH is 7 (neutral)
• amylase:

  • breaks down carbohydrates to glucose
  • produced in salivary glands and small intestine
  • test : iodine test for starch - turns blueblack
  • test: benedict's test for sugars - turns brick red
• protease:

  • breaks down proteins to amino acids
  • produced in pancreas and small intestine
  • test: biuret test for protein - turns brick red
• lipase:

  • breaks down lipids to fatty acids and glycerol
  • produced in pancreas and small intestine
  • test: emulsion test for lipids - add ethanol which results in a cloudy layer
  • test: sudan iii test for lipids - red layer forms on top
• rate of enzymatic reactions:

  • practical
  • rate = change/time