Stabilization of glucose oxidase with cyclodextrin-branched carboxymethylcellulose

we present a methodology for improving some enzymatic characteristics of glucose oxidase (gox) (ec 1.1.3.4). the enzyme was chemically modified with a ？-cyclodextrin-branched carboxymethylcellulose polymer (cmc-cd), using carbodiimide as coupling agent. the obtained neoglycoenzyme had 0.78 mol of polysaccharide per mol of gox and retained 67% of its initial activity. comparison of some characteristics of the modified and free enzymes showed a higher km for derivatized gox and better thermostability, which increased from 45 °c to 51 °c. in addition, derivatization of gox with cmc-cd increased its resistance to inactivation at 45 °c by 2.2-fold, protected the molecule against inactivation with the anionic surfactant sodium dodecylsulphate to the point that it retained 75% of its activity after an incubation of 3 h, and extended its ph tolerance toward alkaline ph (7.5). covalent glycosidation of glucose oxidase with cd-branched carboxymethylcellulose polymer constitutes therefore an effective strategy for enhancing the stability of this enzyme.