Dehydrogenase, E1 component This entry includes a number of dehydrogenases all of which use thiaminepyrophosphate as a cofactor and are members of a multienzyme complex.Pyruvate dehydrogenase (<db_xref db="EC" dbkey="1.2.4.1"/>), a component of the multienzymepyruvate dehydrogenase complex; 2-oxoglutarate dehydrogenase (<db_xref db="EC" dbkey="1.2.4.2"/>),a component of the multienzyme 2-oxoglutarate dehydrogenase which containsmultiple copies of three enzymatic components: 2-oxoglutarate dehydrogenase (E1),dihydrolipoamide succinyltransferase (E2) and lipoamide dehydrogenase (E3);and 2-oxoisovalerate dehydrogenase (<db_xref db="EC" dbkey="1.2.4.4"/>), a component of the multienzymebranched-chain alpha-keto dehydrogenase complex all belong to this family.