Valence and association constant of bovine colostral immunoglobulin M antibody (IgM)

Abstract

Anti-DNP IgM was isolated and purified from bovine colostrum, which was obtained from a cow immunized with dinitrophenylated porcine gamma-globulin, by the use of a cellulose immunosorbent. The valence and the average intrinsic association constant ( K 0) of the antibody was determined employing the monovalent hapten tritiated ϵ-DNP- l-Lysine. The binding of IgM antibody with the latter hapten yielded an equilibrium constant of 2·4 × 10 4 M −1 and revealed that the antibody molecule had five combining sites.