Polyclonal antibodies inhibit the glycation-induced inactivation of bovine Cu,Zn-superoxide dismutase

In vitro incubation of bovine Cu,Zn-SOD (Cu,Zn-superoxide dismutase) with glucose, ribose or fructose results in a remarkable inactivation of the enzyme. There was a progressive decrease in enzyme activity on incubation with glucose and, at the end of 7 days, only 26 of the initial activity remained. The inactivation was accompanied by a parallel decrease in the amount of protein detectable on gels after SDS/PAGE. Reaction of the sugars with SOD was ascertained using an immunoblot assay in which sugar-incubated SOD was derivatized with 2,4-dinitrophenylhydrazine and allowed to react with the dinitrophenol-specific antibody. Affinity purified antibodies from the sera of rabbits immunized with bovine SOD were highly effective in restricting the inactivation of the enzyme induced by glucose, ribose or fructose.