Allotypic variations in the amino acid sequence of rabbit IgG kappa light chains in the region of tryptophan 146

Peptides containing tryptophan 146 from rabbit kappa light chains of b5 and b6 allotypes were Isolated and their sequences determined. Between positions 138 and 161 there is 56% homology between b4 and b9, 64% homology between b5 and b9 and 80% homology between b4 and b5. Between positions 138 and 150 there is 86% homology between b4 and b6 and 93% homology between b5 and b6. This confirms the predictions of serological studies that b9 light chain constant regions would differ most from the other allotypes, while b5 and b6 would be most similar.