Glycation of erythrocyte superoxide dismutase reduces its activity.

purified. Purified SOD was incubated with 1 M glucose at 37 •Ž for 14d under sterile conditions. Nonezymatic addition of glucose to SOD molecules increased linearly until 7 d, and then increased only slightly. The enzyme activity decreased to 88% after 7d and 60% after 14d. The glycated amino acid residue is not the N-terminal a-amino group but the s-amino group of lysine. It seems that lysine at the active center, which assists the interaction of 02and the SOD molecule, is affected during 14d.