Effect of the β-amyloid peptide Aβ25–35 and fullerene C60 on the activity of enzymes in erythrocytes

The effect of the β-amyloid peptide Aβ25–35 and fullerene C60 on the activity of the cytoplasmic enzymes lactate dehydrogenase (LDH) and glutathione peroxidase (GLP), and membrane-bound phosphofructokinase (PFK) and Na+,K+-ATPase in human erythrocytes has been studied. When used in combination, the cytotoxins decrease the activity of LDH and PFK in a nonadditive manner; in this case, Aβ25–35 protects PFK against the inhibitory effect of C60. The activity of LDH, GLP, and PFK decreases within the first 2–20 min of incubation of erythrocytes with Aβ25–35 in the absence of glucose. The addition of glucose sharply decreases the inhibitory action of Aβ25–35 on LDH and GLP but does not affect the fourfold decrease in activity of PFK; the activity of membrane-bound Na+,K+-ATPase does not depend on the presence of glucose. Possible mechanisms of interaction of Aβ25–35 and fullerene C60 with the erythrocyte membrane and enzymes are discussed.