Immunoglobulin M: Identification of an Unusual Fragment Following High Temperature Trypsin Proteolysis

[摘要] A fragment (Int-L) of m.w. 20,000 containing 25% carbohydrate has been identified in (Fc)5µ preparations obtained from high temperature trypsin digests of human λ type IgM molecules. This fragment consists of two disulfide linked components, one related to λ light chains and the second a portion of µ chain which presumably contains the carbohydrate. The intact fragment is univalent with respect to most anti-λ antisera which precipitate it only following reduction of disulfide bonds.The Int-L has not been precisely localized in the IgM molecule. Some evidence indicates it may arise from outside the Fab fragment raising the possibility that it represents a third L chain per IgM subunit.

[学科分类] 生物科学（综合）