Thiol derivatives of cellulose as supports for the immobilization of non-thiol enzymes

Thiosulfate derivatives, which can be reduced with mercaptoacetic acid, are suitable intermediates for the preparation of thiol derivatives of polymers. Thiosulfate derivatives of cellulose were prepared via chlorodeoxy- or via 3-chloro-2-hydroxy-propylcellulose, while mercaptodeoxycellulose prepared via chlorodeoxy derivative had more convenient properties for the immobilization of non-thiol enzymes (acetylcholine esterase, butyrylcholine esterase and trypsin). Before immobilization SH groups were introduced into choline esterases by i) reduction of the cystine residues, ii) reaction with methyl 4-mercaptobutyrimidate, and the isothiocyanate groups were introduced into trypsin on reaction with 3-isothiocyanatopropyl 1-isocyanate. The immobilization of the enzymes treated in this way was carried out under the conditions of the oxidation of thiol groups (i), thiol-disulfide exchange reaction (ii), or an addition nucleophilic reaction of isothiocyanates with thiols. In contrast to the proteolytic activity of the immobilized trypsin the esterolytic activity of immobilized choline esterases attained satisfactory values.