Enzymes that catalyze the transfer of a group $ G $ (other than hydrogen) between a pair of substrates, $ S $ and $ S^{\#} $, are known as transferases. The general reaction is:

$ S-G + S^{\#} \rightarrow S + S^{\#}-G $

Transferases are responsible for transferring functional groups between molecules. In this reaction, the group $ G $ is being transferred from one substrate to another.

Ligases catalyze the linking together of two compounds, such as forming $ \mathrm{C}-\mathrm{O} $, $ \mathrm{C}-\mathrm{S} $, or $ \mathrm{C}-\mathrm{N} $ bonds.

Lyases facilitate the removal of groups from substrates, typically in a manner that leaves double bonds, and they achieve this without hydrolysis.

Hydrolases are enzymes that aid in the hydrolysis of various bonds, including ester, ether, peptide, glycosidic, $ \mathrm{C}-\mathrm{C} $, $ \mathrm{C}- $ halide, or $ \mathrm{P}-\mathrm{N} $ bonds.