A chemical study of rabbit antiovalbumin

Abstract

End-group assay has shown that the immunologically active and inactive fractions of gamma-globulin from rabbit antiovalbumin sera are alike in having one terminal alanyl residue per molecule. In none of the fractions was a significant number of unreactive amino or iminazole groups detected, and they occurred only in small amts. in the specific precipitate. All globulin fractions were alike in having the terminal tetrapeptide alanyl-leucyl-valyl-aspartyl with glutamic acid probably occupying the fifth position. Rupture of the disulfide linkages by reduction with thioglycollate had little effect on the combining power of the antibody, but greatly increased the time of flocculation. The significance of the results is discussed in terms of gamma-globulin structure and theories of antibody formation.