Studies on human IgD myeloma proteins. Carbohydrate composition of intact proteins and some proteolytic fragments.
Human IgD myeloma proteins are shown to have a high carbohydrate content (9-18%) and to exhibit the same heterogeneity in carbohydrate content and composition as myeloma protein of the other immunoglobulin classes. All IgD proteins studied contain N-acetylgalactosamine which is contained in a carbohydrate moiety attached within the "hinge" region of the heavy chain whilst the bulk of the carbohydrate is attached within the Fcdelta region of the molecule.