Mechanism of glucose oxidase immobilization with silk fibroin

Magnetic resonance spectroscopy, NMR and ESR, was applied for the examination of the interaction between glucose oxidase (GOD) and Bombyx mori silk fibroin, in order to analyze the superior attributes of silk fibroin for the immobilization of GOD. The 13C NMR spectra and spin-lattice relaxation times, T₁, of B, mori silk fibroin in aqueous solution did not change in the presence of GOD. The spin-labeled silk fibroin membrane immobilizing GOD gave also the same ESR spectrum as that of the GODfree membrane. In the presence of silk fibroin, the rate of the GOD reaction in aqueous solution monitored by ¹³C NMR slightly decreased, although no peak broadening occurred, indicating a slight decrease in the diffusion of glucose and, as a result, a slight decrease in the contact between glucose and GOD rather than silk fibroin inhibition. In addition, no appreciable interaction was observed between the silk fibroin and 14 kinds of amino acids in the ¹³C NMR spectra.