Preparation of a monoclonal antibody to rat liver glucose-6-phosphate dehydrogenase and the study of its immunoreactivity with native and inactivated enzyme.

A monoclonal antibody of the IgG class was prepared against rat liver glucose-6-phosphate dehydrogenase (G6PD; D-glucose-6-phosphate:NADP+ 1-oxidoreductase, EC 1.1.1.49) by the hybridoma technique. This antibody does not affect the catalytic activity of the enzyme and shows crossreactivity with the palmitoyl CoA-inactivated G6PD. By solid phase radioimmunoassay, the presence of crossreacting materials in comparable amounts was determined in liver homogenate supernatants from rats that had been starved and refed a high-sucrose diet (containing a high level of G6PD activity) and from rats that had been starved and refed a high-fat diet (containing a low level of G6PD activity). These findings indicate that G6PD is present in an inactive form in rats fed a high-fat diet. The monoclonal antibody will facilitate isolation and characterization of the inactive variant G6PD.