INFLUENCE OF THE PEROXIDASE CARBOHYDRATE MOIETY'S OXIDATION CONDITIONS ON COMPOSITION AND PROPERTIES OF INSULIN-PEROXIDASE CONJUGATES
E. B. DIKOVA, E. M. GAVRILOVA, A. M. EGOROV
Chemical Department, M. V. Lomonosov Moscow State University
Abstract: The influence of sodium metaperiodate concentration on kinetics and conversion degree of peroxidase carbohydrate moiety as well as the effect of the oxidation degree of the carbohydrate moiety on the composition, structure and properties of insulin – peroxidase conjugates were studied. The initial rate of peroxidase's oxidation is directly proportional to the periodate concentration; the oxidation rate constant of peroxidase carbohydrate moiety is 1.23×10-3 M-1 min1. At the molar ratio of metaperiodate to peroxidase 150:1 or higher, the maximal quantity of aldehyde groups (62±2) in the peroxidase molecule is formed and the oxidation of each carbohydrate chain leads to the formation of eight aldehyde groups. The molecular mass composition of the insulin—peroxidase conjugates was studied by HPLC. The conjugates proved to be multicomponent mixtures of oligo-mers (53, 83, 128, 174, 268, 440 kD and higher). The insulin—peroxidase molar ratio in the fractions of the conjugates with molecular masses higher than 83 kD is 8:1. It was shown that the affinity of insulin – peroxidase conjugates to antibodies depends on the oxidation degree of peroxidase used for production of conjugates.
Russian Journal of Bioorganic Chemistry 1990, 16 (4):476-481