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Tryptic Fragments of Fc from Normal Human IgG and their Interaction with Staphylococcal Protein A
Author(s) -
ENDRESEN C.,
HEGGENESS M.,
GROV A
Publication year - 1974
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/j.1365-3083.1974.tb01256.x
Subject(s) - chemistry , sephadex , size exclusion chromatography , immunodiffusion , disulfide bond , fragment crystallizable region , immunoglobulin fc fragments , peptide , electrophoresis , antibody , polyacrylamide gel electrophoresis , radial immunodiffusion , microbiology and biotechnology , chromatography , immunoglobulin g , biochemistry , enzyme , biology , immunology , receptor
Tryptic digests of acid‐treated Fc from normal human IgG were separated into four peaks (I to IV) by gel filtration on Sephadex G‐100. Essentially all the material from peak I reacted with staphylococcal protein A. had a molecular weight (MW) of approximately 55,000, and was indistinguishable from intact Fc on electrophoresis and immunodiffusion. Peaks II and III, MW 42,000 and 32,000. respectively, contained both protein A‐reactive and protein A‐nonreactive material, whereas peak IV. MW 12,000, showed no reaction with protein A The protein A‐reactive material from peaks II and III had an intact Fc chain bound to another peptide, from which a part of the C‐terminal sequence had been removed. The protein A‐nonreactive material from peaks II and III lacked antigenic determinant(s) compared to intact Fc and gave fragments with MWs of 16.000 and 18,000. respectively, after reduction, suggesting that these fragments consist of Fc N‐terminal sequences joined by disulfide bonds. It is concluded that, in contrast to interchain interaction, intrachain interactions influence protein A activity.