| Oxyreductases | catalyse redox reactions (for example: glucose-oxidase) |
| Transferases | transport functional groups of a donator to a receiver |
| Hydrolases | split molecules (for example: peptidases, proteases) |
| Liases | distract or add: certain functional groups (for example: decarboxylase) |
| Isomerases | change isomeres (mutase) |
| Ligases | connect different molecules with each other (piruvaate carboxylase) |