Activation of polysaccharides with 2-iminothiolane and its uses

2-Iminothiolane, a cyclic thioimidate, is known to react readily with amino groups of proteins to give amidinated derivatives containing reactive sulfhydryl groups. In this report it will be shown that 2-iminothiolane also reacts with hydroxyl and sulfhydryl groups. Such a reaction with hydroxyl groups can be used to introduce sulfhydryl groups into polysaccharides. When this reaction is carried out in the presence of 4,4'-dithiodipyridine, polysaccharides containing 4-dithiopyridyl groups can be prepared. These activated polysaccharides couple easily via intermolecular disulfide bond formation with proteins containing thiol or 4-dithiopyridyl groups. The resulting polysaccharide--protein conjugates have good stability, and they are useful reagents for different biochemical applications such as the purification of proteins containing thiol groups and affinity chromatography.