Immunological Studies of Modified and Enzymically Degraded beta-Lactoglobulin and alpha-Lactalbumin.

Abstract

[alpha]-Lactalbumin and [beta]-lactoglobulin were modified by dinitrophenylation, acetylation or esterification. Immune electrophoretic studies of the modified proteins indicated that a modification of amino groups did not necessarily inhibit the immunoprecipitation reaction with antibodies against the native proteins. Esterification of carboxyl groups in the proteins diminished their ability to form immunoprecipitates. Studies of tryptic hydrolysates of native or acetylated [beta]-lactoglo-bulin did not reveal any fragment with ability to precipitate with antibodies against the native protein. Similar studies on [alpha]-lactalbu-min demonstrated several precipitation lines, but only one of them was obviously formed by native [alpha]-lactalbumin, whereas the others were due to trace impurities of serum albumin in the preparation.