sentences:  More specifically, the C4B has shown to react much more efficiently and effectively despite the 7 kb difference between C4A and C4B.In whole serum, C4B alleles performed at a rate several fold greater during hemolytic activity, in direct comparison with C4A alleles.Biochemically, they also found that C4A reacted more steadily with an antibody’s amino acid side chains and antigens that are amino groups, while C4B reacted better with carbohydrate hydroxyl groups.