Portal de Periódicos da CAPES

The Inhibition of Beef Liver Glutamic Dehydrogenase by Metal-binding Agents

1959; Elsevier BV; Volume: 234; Issue: 4 Linguagem: Inglês

10.1016/s0021-9258(18)70183-x

1083-351X

S. James Adelstein, Bert L. Vallée,

Drug Transport and Resistance Mechanisms

Crystalline preparations of the glutamic dehydrogenase of beef liver contain from 2 to 4 gm. atoms of zinc per mole of enzyme protein (1). The dependence of the catalytic activity of glutamic dehydrogenase on the metal is inferred from (a) the concomitant increase of zinc to protein and activity to protein ratios during its crystallization and (b) the inhibition of enzyme activity by agents which form stable complexes with zinc ions in aqueous solutions. In this report the inhibition of glutamic dehydrogenase by metal-binding agents, including 1, IO-phenanthroline, is shown to depend on the ability of these agents to form a complex with zinc ions and to be qualitatively similar to that observed with yeast alcohol dehydrogenase, another zinc metallobehydrogenase. A mechanism for the inhibition of glutamic dehydrogenase by metal-binding agents similar to that observed for another zinc metallodehydrogenase, yeast alcohol dehydrogenase, (2, 3) is proposed, although glutamic dehydrogenase differs from alcohol dehydrogenase both with respect to the reaction it catalyzes and its protein size and structure.