Dissociation of kappa- and lambda-chains from reduced human immunoglobulins.

1. The light chains of human immunoglobulin (Ig) exist in two forms, kappa (type K) and lambda (type L). The two types of chains can be partially separated by taking advantage of the fact that lambda-chains, for the most part, dissociate from reduced Ig at higher pH than do the kappa-chains. The same difference in dissociation of type K and L chains was observed with myeloma IgG and IgA proteins, but not with pathological IgM proteins. 2. When analysed in urea-glycine starch gels, pH7, both kappa- and lambda-chains show ten electrophoretic bands having the same mobilities as those of the whole light-chain subfractions. Normal kappa- and lambda-chains show similar differences in overall amino acid composition to those previously found with myeloma kappa- and lambda-chains and type K and L Bence-Jones proteins.