how they help enzymes work

• some enzymes will only work if there is another non-protein substance bound to them - cofactors
• • some cofactors are inorganic molecules or ions.
  • they help the enzyme and substrate bind together
  • don't directly participate in the reaction so aren't used up or changed
  • e.g. chloride ions are cofactors for amylase
• some cofactors are organic molecules - coenzymes

  • participate in a reaction and are changed by it
  • act as carriers moving chemical groups between different enzymes
  • continually recycled
  • vitamins are often sources of coenzymes
• • if a cofactor is tightly bound to an enzyme its the prosthetic group
  • zinc ions are a prosthetic group for carbonic anhydrase. zinc ions are a permanent part of the enzymes active site