Similarity between tryptic peptides derived from equine mu and rabbit gamma chains of affinity labeled antilactose antibodies of restricted heterogeneity.

Equine IgM and rabbit IgG antilactose antibodies of restricted heterogeneity were affinity labeled with two different bromoacetyl lactose reagents. Tryptic peptides derived from the heavy chains of the antibodies were analyzed for their amino acid compositions. Surprisingly they were quite similar. The possible genetic implication of this interesting observation is briefly discussed.