Abstract

MATOS, Madyu et al. Stabilization of glucose oxidase with cyclodextrin-branched carboxymethylcellulose. Biotecnol Apl [online]. 2012, vol.29, n.1, pp.29-34. ISSN 1027-2852.

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 ß-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.

Keywords : Carboxymethylcellulose; cyclodextrin; enzyme stability; glucose oxidase.

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