We studied the effect of aclacinomycin on human erythrocyte membrane enzymes. Aclacinomycin inhibited ATPase, including Na-K-dependent ATPase, ouabain insensitive ATPase and Ca-ATPase. However acetylcholinesterase was not inhibited by aclacinomycin. The ATPase activities were not inhibited by aclacinomycin if ascorbate was added to the incubation mixture. However other reducing agents, alpha-tocopherol, superoxide dismutase and catalase had no effect on ATPase activity. Ascorbate may protect membrane proteins and lipids from peroxidate damage.
Two NADH diaphorases, diaphorase I and II, were isolated from normal red cells and congenital methemoglobinemic red cells by CM-cellulose and DE 32 column chromatography. For methemoglobinemic sample, activities of diaphorase I and diaphorase II were 80% and less than 5% of those for the normal red cells, respectively. Only diaphorase II showed cytochrome b5 reductase activity. The cytochrome b5 reductase deficiency seems to manifest methemoglobinemia through the decrease in the enzymatic reduction of cytochrome b5 and subsequent nonenzymatic reduction of methemoglobin by the reduced cytochrome b5. The methemoglobinemic diaphorase II was found similar to the normal enzyme with respect to Kms for the dye and NADH, heat stability, effect of pH, and electrophoretic pattern. The ratio of the diaphorase activity to the cytochrome b5 reductase activity was the same for both enzymes. Although the production of an abnormal enzyme molecule can not be excluded, it is possible that in this case the rate of enzyme formation is decreased.
Wheat germ agglutinin (WGA) agglutinated the L1210 leukemic cells and daunomycin entrapped erythrocytes in vitro. Comparing with control preparations, the greatest increase in survival was obtained in vivo when the daunomycin entrapped erythrocytes and WGA were given to BDF1 mice bearing L1210 cells.
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