Structural Biochemistry/Enzyme Catalytic Mechanism/Enzyme Classification/Transferases
A transferase is an enzyme that aids in the transferring of a functional group from one molecule to another. The functionl group detaches from the donor molecule and forms a bond with the acceptor through catalytic pathways. The donor molecule is usually small non-protein molecules known as coenzymes.
As the name states, transferases transfer functional groups, such as amino group, acyl group, phosphate group, and glycosyl group, between donors and acceptors.
A page with a list of transferases can be found here 
Nomenclature and Classification
Transferases are commonly labeled as acceptor transferases or donor transferases depending on the target transfer. Functional groups can also be found in the name describing the functional group that the transferase transfers. There is also a classification system in which transferases are organized. This system is called the EC system. In this system there are 9 subgroups each beginning with EC 2. They are mainly organized by the functional groups that they transfer.