Enzymes

• Enzymes are tertiary structure proteins that lower the activation energy of the reaction they catalyse
• enzymes have a specific active site due to the specific folding and bonding in tertiary structure

  the location of bonds is determined by primary structure

  this means they only bind to substrate with complementary shape
• induced fit model

  when an enzyme substrate complex forms, the enzyme slightly changes shape to mould around substrate

  this puts strain on the bonds and lowers activation energy
• temperature

  too high - enzyme denature, the active site changes shape and enzyme substrate complex’s cant form

  too low - not enough Kinect energy for successful collisions between enzyme and substrate
• pH

  if the pH is too high or low it will interfere with the charges in amino acids in the active site, this can break bonds that holds the tertiary structure so the active sit changes shape

  the enzyme denatures and fewer complexes form

  different enzymes have different optimal pHs
• enzyme and substrate concentration

  if there is insufficient substrates, the reaction will be slower as there will be fewer collisions

  if there is insufficient enzymes, the active sites will become saturated with substrates faster and wont be able to work faster
• enzyme inhibitors

  Competitive - same shape as substrate, binds to active site so complex’s cant form. More substrate decreases its effects

  non-competitive - binds to allosteric site and causes active site to change, increases substrate wont have an effect as active site has changed shape so it can’t form complexes