Enzymes fall into classes based on function
There are 6 major classes of enzymes:
  1.Oxidoreductases which are involved in oxidation,
reduction, and electron or proton transfer reactions;
   2.Transferases, catalysing reactions in which groups are
transferred;
   3.Hydrolases which cleave various covalent bonds by
hydrolysis; 4
  4.Lyases catalyse reactions forming or breaking double
bonds;
  5.Isomerases catalyse isomerisation reactions;
   6.Ligases join substituents together covalently.