Optimization of dextran and mannan dialdehydes preparation and examinationof their biospecific interaction with Concanavalin A

The periodate oxidation of dextran and mannan was optimized to prepare acti vated polysaccharides (containing aldehyde groups) suitable for conjugation with proteins. The mild reaction conditions to achieve available degree of oxidation, while the depolymerization was prevented, were estimated. The p roducts containing up to 16 aldehyde groups per dextran molecule and up to 28 aldehyde groups per mannan molecule were obtained, while a low decrease of M-r of both polysaccharide chains, from 18 400 to 17 000 of dextran and from 55 000 to 49 500 of mannan, respectively, was observed. Using the precipitation method the interaction of Concanavalin A with both. original as well as modified, subsequently reduced, dialdehyde polysacchar ides was investigated. Only the precipitation of mannan and its modified fo rm with Concanavalin A was observed. The oxidation of mannan up to 20 aldeh yde groups per mannan molecule caused only a very little decrease of affini ty of prepared samples to Concanavalin A.