[Influence of glutathione on the catalytic properties of leucine aminopeptidase].
1. Leucine aminopeptidase does not catalyze the hydrolysis of glutathione. 2. Glutathione inhibits the hydrolysis of the substrates leucine hydrazide and leucine-p-nitroanilide by leucine aminopeptidase. 3. By means of kinetic experiments the type of the inhibition has been determined as noncompetitive. The inhibition constant Ki for the Mg2+-activated enzyme is five times higher than for the non-activated enzyme. 4. The degree of inhibition caused by glutathione depends on the pH value indicating a competition between glutathione and OH- ions. Mg2+-activated enzyme is invariably inhibited in the investigated pH range of 7.2 to 9.8. 5. A preincubation of the enzyme with glutathione changes the degree of activity enhancement by metal ions.
D000818:Animals; D002417:Cattle; D004789:Enzyme Activation; D005978:Glutathione / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007908:Lens, Crystalline / Q000201:enzymology; D007931:Leucyl Aminopeptidase / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology
D007931:Leucyl Aminopeptidase; D005978:Glutathione; D008274:Magnesium
Untersuchungen zum Einfluss von Glutathion auf die katalytischen Eigenschaften der Leuzinaminopeptidase