Binding Constants of NZB Myeloma Antidextrans for Dextrans and Isomaltose Oligosaccharides Determined by Affinity Electrophoresis

Abstract

Association constants of dextrans (Ka) and oligosaccharides (Kia) from NZB myeloma antidextrans (PC3858 and PC3936) were studied by affinity electrophoresis. With linear dextrans or with those with a low degree of branching, Ka ranged from 2.7 × 103 to 5.4 × 104 ml/g for PC3858 and from 1.3 × 104 to 2.6 × 105 ml/g for PC3936. Completely linear α-(1 → 6)-linked dextrans, LD7 and D3, showed relatively high affinities for the two NZB antidextrans. With oligosaccharides, the Kia value increased as the number of α-(1 → 6)-linked glycosyl residues increased. Isomaltoheptaose (IM7) showed the highest Kia (1.9 × 104 M-1 for PC3858 and 1.63 × 104 M-1 for PC3936), whereas isomaltose (IM2) had the lowest Kia (2.36 × 102 M-1 for PC3858 and 1.32 × 102 M-1 for PC3936). Pullulan and glycogen showed very weak affinity for PC3936, but they did not react at all with PC3858. These findings indicate that NZB myeloma antidextrans, PC3858 and PC3936, are specific for internal chains of α-(1 → 6)-linked dextrans. Data on the precision with which Ka and Kia can be determined are presented.