Regulation of Glucose Oxidase Activity through Interaction with Fullerene Derivatives

The 2-（hydroxymethyl）pyridine modified C60 （PY-C60） and methoxydiglycol modified C60 （MDG-C60） are synthesized using Bingel-Hirsch reaction and characterized by nuclear magnetic resonance （NMR） and mass spectra. PY-C60 and MDG-C60 can bind to glucose oxidase （GOx） and quench the fluorescence of tryptophan （Trp） residue in GOx through static mechanism. The conformation of GOx is disturbed after formation of complex with these fullerene derivatives. Kinetic analysis indicates that PY-C60 and MDG-C60 may affect the catalytic activity of GOx with a partial mixed-type inhibition mechanism. In the plasma glucose concentration range （3.6--5.2 mmol·L-1）, PY-C60 may significantly accelerate the catalytic velocity of GOx, however, MDG-C60 exerts almost no obvious change to the initial velocity of GOx, suggesting that elaborate design of molecular structure of fullerene derivative is very important for regulating the biological activity of fullerene-enzyme complex.