The C-terminal sequences of the heavy chains of human immunoglobulin G myeloma proteins of differing isotopes and allotypes.
The sequences of the C-terminal octadecapeptides obtained by cyanogen bromide cleavage of the gamma-chains of myeloma proteins of the four subclasses, and a urinary heavy-chain-disease protein, have been determined. Although the sequences were markedly homologous, unique replacements were identified that distinguished between the gamma(2b), gamma(2c) and gamma(2d) subclasses. The data are in accord with the postulated existence of four genetic loci or cistrons, these having arisen by the process of gene duplication.
Prahl
J W
JW
Department of Immunology, St Mary's Hospital Medical School, London, W. 2.