<p> One pathway for the assimilation of ammonia and glutamate biosynthesis involves homotetrameric glutamate synthase (<db_xref db="EC" dbkey="1.4.1.13"/>) which transfers the amide group of glutamine to 2-oxoglutarate to yield two molecules of glutamate [<cite idref="PUB00015574"/>]. <reaction> 2 L-glutamate + NADP⁺ = L-glutamine + 2-oxoglutarate + NADPH + H⁺.</reaction> </p> Glutamate synthase (NADPH), homotetrameric