Effect of a protease inhibitor on the stability of catalase in liver and blood from acatalasemic and normal mice.

Effects of Gabexate mesilate (GM) (([ethyl-4-(6-guanidino hexanoyloxy) benzoate] methane sulfonate)), a protease inhibitor, on the activities of catalase in liver, erythrocytes and reticulocytes from acatalasemic mice were examined. Preincubation without GM at 37 degrees C for 160 min lowered the catalase activities of liver, erythrocytes and reticulocytes from acatalasemic mice, to 24%, 40% and 10% of the initial levels, respectively. But, preincubation with GM at 37 degrees C for 160 min delayed the rapid decrease in activities of residual catalases in the liver, erythrocytes and reticulocytes of acatalasemic mice to 65%, 93% and 85% of the initial values, respectively. At 20 degrees C or below, no reduction in catalase activity of reticulocytes from acatalasemic mice occurred with or even without GM. At pH 5.0, the decrease in catalase activity of acatalasemic mice was small both in the presence and the absence of GM. In the alkaline range, the reduction in the enzyme activity of the mutant mice without GM was enhanced with increase in pH values up to 8.5. But the presence of GM during preincubation at pH 7.5, retained the catalase activity of acatalasemic mice, to 64% of the activity at pH 6.5. These data suggest that some factors affected by GM, might be responsible for the low stability and activity of catalase in the acatalasemic mice.