Open AccessThe Parallel Nature of the Interchain Disulphide Bonds of Immunoglobulins
Author(s) -
Svasti Jisnuson,
Milstein Cesar
Publication year - 1972
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1972.tb02547.x
Subject(s) - cystine , chemistry , peptide bond , thermolysin , peptide , amino acid , myeloma protein , hydrolysis , biochemistry , antibody , cysteine , trypsin , enzyme , biology , immunology
[ 35 S]Cystine‐labelled MOPC 21 (IgGl:χ) myeloma protein was prepared by incubating myeloma cells, grown as a suspension culture, in medium containing [ 35 S]cystine. The radioactive protein was used as a tracer in conjunction with carrier myeloma protein. A peptic‐tryptic peptide of 36 residues was prepared, which contained ten half‐cystine residues and included the heavy‐light and all the heavy‐heavy inter chain disulphide bridges of the molecule. The peptide was digested with thermolysin and subjected to partial acid hydrolysis. A large number of small peptides was isolated and, when possible, their amino acid compositions were determined. From 170 possible arrangements of the disulphide bonds a unique arrangement was deduced in which all the heavy‐heavy interchain bonds were parallel. This is the first case in which the arrangement of all the interchain bonds of any of the human or mouse IgG subclasses has been established.