Forms L-glutamate from L-glutamine and 2-oxoglutarate. Represents an alternative pathway to L-glutamate dehydrogenase for the biosynthesis of L-glutamate. Participates with glutamine synthetase in ammonia assimilation processes. The enzyme is specific for NADH, L-glutamine and 2-oxoglutarate. 2 L-glutamate + NAD(+) = 2-oxoglutarate + H(+) + L-glutamine + NADH Binds 1 [3Fe-4S] cluster. Inhibited by homocysteine sulfonamide. Optimum pH is 7-7.5. Active from pH 6 to 9. Amino-acid biosynthesis; L-glutamate biosynthesis via GLT pathway; L-glutamate from 2-oxoglutarate and L-glutamine (NAD(+) route): step 1/1. Energy metabolism; nitrogen metabolism. Homotrimer. Present with 18900 molecules/cell in log phase SD medium. Belongs to the glutamate synthase family.