Catalyzes the conversion of 2-oxoglutaramate to 2-oxoglutarate. Together with glutamate dehydrogenase, may form a physiologically relevant enzyme couple, leading to transformation of metabolically inert 2-oxoglutaramate derived from trihydroxypyridine into glutamate, a central compound of nitrogen metabolism. 2-oxoglutaramate + H2O = 2-oxoglutarate + NH4(+) Alkaloid degradation; nicotine degradation. Belongs to the carbon-nitrogen hydrolase superfamily. NIT1/NIT2 family.