An investigation was attempted to determine the effects of triethanolamine, monoethanolamine, ammonium sulfate, hydrazine hydrate and hydroxylamine hydrochloride on the enzyme activity of glutamic acid dehydrogenase which is a pyridine enzyme playing an important role in the oxidation and reduction of living bodies. Results obtained were as follows:
1) Sodium glutamate and DPN were dissolved in a potassium phosphate buffer solution. Immediately after addition of the enzyme solution to the buffer, each of the above reagents in different concentrations was added to determine the effects of the mixtures on the enzyme activity for 6 minutes. Triethanolamine, monoethanolamine and hydrazine hydrate enhanced the enzyme activity. The largest increase, about 46%, was observed in the monoethanolamine mixture at the final concentration of 3.3×10 -2 M. The second largest increase was found in triethanolamine and the smallest in hydrazine hydrate.2) Hydroxylamine hydrochloride and ammonium sulfate inhibited the activity of glutamic acid dehydrogenase; ammonium sulfate inhibited the enzyme activity by about 50% at the final concentration of 5.0×10 -3 M, and the percentage was higher than that caused by hydroxylamine hydrochloride.