Involved in arginine catabolism by converting L-glutamate, into 2-oxoglutarate, which is then channeled into the tricarboxylic acid cycle. H2O + L-glutamate + NAD(+) = 2-oxoglutarate + H(+) + NADH + NH4(+) Belongs to the Glu/Leu/Phe/Val dehydrogenases family.