Oriented immobilization of glucose oxidase on graphene oxide

The oriented immobilization of glucose oxidase (GOD) on a selective support composed of graphene oxide (GO) and concanavalin A (Con A) was prepared in this study. Specially, the amino groups of Con A were covalently attached to the carboxyl groups of pre-activated GO, and then GOD was oriented immobilized on the GO-Con A conjugate via strong biospecific affinity between the sugar residues of GOD and Con A. Compared with free GOD and randomly immobilized GOD (GO-GOD), the high-affinity of Con A and GOD endowed the oriented immobilized GOD (GO-Con A-GOD) with a wider pH stability range, a better thermal stability, a longer-term storage stability and a higher resistance ability toward the denaturing agents. The Michaelis constant (K-m) of GO-Con A-GOD was very close to that of free GOD. Hopefully, the GO-Con A-GOD may be further integrated into functional bioelectrodes for biosensor applications. (C) 2012 Elsevier B.V. All rights reserved