[Effect of ammonium chloride on NDP(P)+-dependent glutamate dehydrogenase from bovine liver]

It was shown that NAD(P)(+)-dependent glutamate dehydrogenase from bovine liver (EC 1.4.1.3) was activated under the action of ammonium chloride in concentration which corresponded to the level of ammonium in normal blood (2-10 mM). Ammonium chloride increases the activity of glutamate dehydrogenase 1.8 times. Having enhanced the level of ammonium chloride to the amount which corresponds to the level of ammonium ions in blood during the pathology (10-25 mM), this substance inhibited the enzyme activity of glutamate dehydrogenase. Influence of 20 mM ammonium chloride on IR-spectra of NAD(P)(+)-dependent glutamate dehydrogenase in the deuterium oxide solution leads to the widening of the absorption line at 3300 cm-1 toward the higher energy. It is supposed that inhibition action of ammonium ions on the activity of glutamate dehydrogenase is connected with partial destruction of stereoregular hydrogen bonds in the enzyme molecule.