What product is formed when $\mathrm{NH}_4^{+}$reacts with $\alpha$-ketoglutaric acid?

In biosynthesis of amino acids, inorganic ammonium nitrogen is incorporated to organic acid to form amino acid glutamate. In reductive deamination, ammonium ion combine directly with carboxylic acid (e.g.) intermediate of Krebs' cycle, $\alpha$-ketoglutaric acid). The reaction is catalysed by enzyme glutamate dehydrogenase and $\mathrm{NADPH}+\mathrm{H}^{+}$ acts as hydrogen donor.