EC 2.6 Transferring nitrogenous groups
This subclass contains enzymes that transfer a nitrogenous group from a donor to an acceptor. Most enzymes in this subclass belong in EC 2.6.1, which is for enzymes that transfer amino groups from a donor, generally an amino acid, to an acceptor, generally a 2-oxo acid. It should be kept in mind that transamination by this reaction also involves an oxidoreduction; the donor is oxidized to a ketone, while the acceptor is reduced. Nevertheless, since the transfer of the amino group is the most prominent feature of this reaction, these enzymes have been classified as aminotransferases rather than oxidoreductases (transaminating). Most of these enzymes are pyridoxal-phosphate proteins. Sub-subclasses are based on the type of nitrogenous group that is transferred: transaminase (EC 2.6.1), oximinotransferase (EC 2.6.3) and other nitrogenous groups (EC 2.6.99).