The design of enzyme sensors based on the enzyme structure.

The size of some of the reported electron mediators for glucose oxidase compared with the available space to penetrate the active site, implies that electrons have to move along the protein structure. Theoretical and experimental evidence predicts that it is possible to have electron transfer at the required rate used in biosensors (200 to 1840 electrons s-1) for the distances in glucose oxidase (20 to 25 A). Use of the program "Pathways" (together with the knowledge of the enzyme structure) allowed us to find an electron pathway within the enzyme. This pathway has a maximum electron coupling between the active site and the surface of the enzyme. The pathway reaches the surface near functional groups that can be used for oriented immobilization of the enzyme. Experimental confirmation of this particular pathway has been attempted but it is still elusive.