E2 component of the 2-oxoglutarate dehydrogenase (OGDH) complex which catalyzes the second step in the conversion of 2-oxoglutarate to succinyl-CoA and CO(2). (R)-N(6)-dihydrolipoyl-L-lysyl-[2-oxoglutarate dehydrogenase complex component E2] + succinyl-CoA = (R)-N(6)-(S(8)-succinyldihydrolipoyl)-L-lysyl-[2-oxoglutarate dehydrogenase complex component E2] + CoA Binds 1 lipoyl cofactor covalently. Amino-acid degradation; L-lysine degradation via saccharopine pathway; glutaryl-CoA from L-lysine: step 6/6. Forms a 24-polypeptide structural core with octahedral symmetry. Part of the 2-oxoglutarate dehydrogenase (OGDH) complex composed of E1 (2-oxoglutarate dehydrogenase), E2 (dihydrolipoamide succinyltransferase) and E3 (dihydrolipoamide dehydrogenase); the complex contains multiple copies of the three enzymatic components (E1, E2 and E3). Belongs to the 2-oxoacid dehydrogenase family.