Studies of Mercaptoethanol-Dissociated Normal Human 19 S γGlobulin and Pathologic Macroglobulins from Patients with Macroglobulinemia

Abstract

Summary: Following reductive cleavage of normal 19S γ-globulin and four pathologic macroglobulins with mercaptoethanol, the dissociated fractions could be separated into three distinct components by chromatography on diethylaminoethyl (DEAE)-cellulose. Fractions 1 and 2 had s rates of approximately 8S whereas fraction 3 appeared to represent heterogeneous low molecular weight substances. The fragments shared certain antigenic groups with 7S γ-globulin. However, they differed from it in antigenic and electrophoretic properties, sedimented more rapidly in the ultracentrifuge and contained greater amounts of hexose. Fractions 1 and 2 generally differed from each other and the native macroglobulin in electrophoretic behavior and hexose content. The fragments of four of five proteins studied were antigenically deficient when compared to the native protein but could not be distinguished immunologically when compared to each other. The possible relationship of these structural units to the electrophoretic mobility of the native protein is discussed. The existence of several distinct 7 to 8S components, derived from the normal 19S γ-globulins, each of which differs from 7S γ-globulin, offers additional evidence for the existence of at least two major groups of immune globulins.