In enzymology, a glutamate synthase (NADPH) (EC 1.4.1.13) is an enzyme that catalyzes the chemical reaction Thus, the four substrates of this enzyme are L-glutamine, 2-oxoglutarate (α-ketoglutarate), NADPH, and H+, whereas the two products are L-glutamate and NADP+.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH2 group of donors with NAD+ or NADP+ as acceptor.

It occurs in bacteria and plants but not animals, and is important as it provides glutamate for the glutamine synthetase reaction.

[1][2] The systematic name of this enzyme class is L-glutamate:NADP+ oxidoreductase (transaminating).

Other names in common use include: As of late 2007, only one structure has been solved for this class of enzymes, with the PDB accession code 1EA0.