Structure of Human Immunoglobulin M

[摘要] A 10.6 S fragment with an approximate molecular weight of 320,000, which represented the Fc portion of the human IgM was isolated by digesting the IgM in the absence of cysteine with activated papain. Comparison of antigenic properties, amino acid composition and carbohydrate content of this fragment with those of the Fc fragment obtained from the subunits of IgM previously, indicated that this 10.6 S fragment was composed of the Fc portions of IgM subunits. The 10.6 S fragment dissociated into 3.2 S Fc units by mild reduction followed by alkylation. Thus it was evidenced that the intersubunit disulfide bonds of IgM are located on the Fc portions of the subunits.

[学科分类] 生物科学（综合）