Glutathione metabolism. 1. The glyoxalase activity of mature mammalian erythrocytes

Abstract

The glyoxalase activity of intact and lysed human erythrocytes was studied. Conditions are described under which the glyoxalase activity of intact erythrocytes proceeds at a constant rate, independent of the methylglyoxal and sodium bicarbonate concentrations and directly proportional to the erythrocyte concentration. The system may be used as a sensitive assay of the enzyme-coenzyme activity of the cell. Lysed erythrocytes react similarly only in the presence of low concentrations of added glutathione. The rate of glyoxalase activity in the presence of relatively high concentrations of glutathione increases with the methylglyoxal and sodium bicarbonate concentrations and is no longer proportional to the enzyme concentrations. Further, the reaction rate decreases with time. An inhibitory effect of methylglyoxal on the glyoxalase system is described.