COVALENT ELECTROPOLYMERIZATION OF GLUCOSE-OXIDASE IN POLYPYRROLE

Glucose oxidase (GOx) has been chemically derivatized by coupling N-(2-carboxyethyl)pyrrole to surface lysyl residues with a corbodiimide-promoted reaction. The modified enzyme (30.2 +/- 0.5 mol of pyrrole/mol of GOx) displayed almost identical properties to the native enzyme except that the pI was slightly more acidic and the stability was 6-fold higher at pH 7.0 and 60-degrees-C. The protein-substituted pyrroles were accessible to electrochemical oxidation and in the presence of free pyrrole generated copolymers which covalently incorporated GOx. This new procedure incorporated more enzyme activity into the conducting polymer than the previously reported physical entrapment technique at equivalent enzyme concentrations in the polymerization media. The covalently entrapped enzyme was 171-fold more stable than the soluble native enzyme and was used to generate a glucose-sensitive electrode.