New insulin-releasing system on the basis of the redox reaction of glucose was synthesized by immobilizing insulin through a disulfide bond(5, 5`-dithiobis(2-nitrobenzoic acid) to polymer membrane(poly(methyl methacrylate)) and enzyme(glucose oxidase)...
New insulin-releasing system on the basis of the redox reaction of glucose was synthesized by immobilizing insulin through a disulfide bond(5, 5`-dithiobis(2-nitrobenzoic acid) to polymer membrane(poly(methyl methacrylate)) and enzyme(glucose oxidase). The disulfide bonds were cleaved upon oxidation of glucose with glucose dehydrogenase and glucose oxidase, releasing insulin from the membrane and enzyme. Sensitivity to glucose concentration was enhanced by coimmobilization of enzyme cofactors(nicotinamide adenin dinucleotide and flavin adenin dinucleotide) acting as electron mediator(for the membrane device), and further enhanced by direct immobilization of insulin on glucose oxidase(for the protein device). Both systems were specific to glucose, and the released insulin was indistinguishable from native insulin. The biological activity of released insulin was 81% of native insulin.