Department of Biological Sciences Stanford University, Stanford, California 94305 USA
Abstract:
This report describes the development of a series of monoclonal antibodies to rat liver 3-Hydroxy-3-methylglutaryl-CoA reductase (HMGR). Sera from hybridoma tumor-bearing mice were used to remove and characterize HMGR activity from a mixture of rat liver proteins. Two IgG2 monoclonal antibodies removed separately greater than 80% HMGR activity while non-immune mouse or negative hybridoma-derived sera were ineffective. Radiolabeled immunoprecipitates of enzyme preparations resolved in one- and two-dimensional SDS-PAGE showed two predominant subunits at Mr 52,000 and 54,000. Our results indicate that in these preparations of rat liver proteins HMGR exists as a heteropolymer with at least two distinct subunits of different molecular weights.