The Reductive Dissociation of Rabbit Immune Globulin in Sodium Dodecylsulfate

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Abstract
Summary: Reduction of rabbit immune globulin in the presence of dodecylsulfate resulted in the separation of antigenic sites present in the intact molecule. Components having an s20 of 3.8 S and 2.5 S appeared upon reduction whereas in the absence of reducing agent γ-globulin in detergent alone had an s20 of 5.5 S. Anti-lysozyme or anti-phage globulin retained full antibody activity after reduction in detergent and subsequent alkylation. Partial separation of components of reduced γ-globulin was achieved by gel filtration. Antibody activity was found to be associated mainly with the smaller components of the mixture, which included “B-chains,” chains with I-type antigenic sites related to “A-chains,” and separate chains containing III-type antigenic sites. No convincing antibody activity could be demonstrated with preparations of “A-chain” or “B-chain” obtained by reduction and propionate dissociation. This “B-chain” fraction appeared to contain components which existed in pairs in solution. Between pH 3.7 and 2.4 the “B-chains” dissociated. A similar pairing in neutral buffers and dissociation in 1 M propionic acid was indicated for components in the antibody-active fractions obtained by reduction of γ-globulin or Fragment I in the presence of detergent. In some instances, antibody-active components which remained dissociated after removal of detergent were obtained by reduction of γ-globulin. These components had MW = 20 to 27,000. Ion exchange chromatography of the smaller components obtained from γ-globulin by reduction in detergent yielded fractions containing principally “B-chains.” These fractions retained antibody activity.