enyzmes

• structure of enzymes?

  • globular proteins
  • specific active site - complimentary to specific substrate
  • active site determined by tertiary structure
• function of enzymes?

  • biological catalysts - increase rate
  • form enzyme substrate complexes
  • reducing activation energy
• induced fit hypothesis?

  • active site isn't directly complimentary
  • therefore is flexible
  • conformational change causes enzyme substrate complex to form
  • puts strain on substrate bonds
  • reducing activation energy
• factors affecting enzyme activity

  • substrate concentration
  • inhibitors
  • temperature
  • pH
  • enzyme concentration
• how does temperature affect enzyme activity?

  • rate increases
  • enzymes gain kinetic energy until optimum
  • after optimum, hydrogen + ionic bonds break
  • tertiary structure changes
  • enzyme denatures - no longer complimentary
• how does pH affect enzyme activity?

  • have a narrow optimum range
  • outside optimum, H+ and OH- ions interact with hydrogen bonds
  • changing tertiary structure
  • enzyme denature - no longer complimentary
• how does substrate concentration affect enzyme activity?

  • higher the substrate concentration, more enzyme substrate complexes form
  • increases rate
  • rate levels off when max no. of enzyme substrate complexes form
• how enzyme concentration affect enzyme activity?

  • higher the enzyme concentration, more frequent collisions
  • faster rate
• what is a catalyst?


  • speeds up rate of reaction
  • without being used up
  • reduces activation energy
• what is activation energy?


  • minimum energy required for a reaction to occur
  • by breaking bonds
• how do competitive inhibitors?

  • binds to active site of enzyme due to similar shape
  • substrate cant bind to enzyme
  • cant form enzyme substrate complexes
  • more competition
• how do non competitive inhibitors work?

  • bind to allosteric site
  • trigger conformational change at active site
  • no longer complimentary
• what is end product inhibition?

  one product of reaction acts as inhibitor
• how and why do you calculate initial rate?

  how?

  • gradient of the tangent at 0

  why?

  • shows maximum rate before concentration of reactants decreases rapidly