To elucidate the inactivation mechanism of mushroom polyphenoloxidase by γ-irradiation, enzyme solutions were irradiated at 1, 3, 5, 7, and 10 kGy, and molecular properties such as secondary and tertiary structures were examined. irradiation above 5 kGy decreased the enzyme activity by more than 93. Circular dichroism study showed that increase of radiation increased the ellipticity values in the range of 210 and 225 nm, resulting in decrease of the ordered structure of the enzyme. Fluorescence spectroscopy indicated that irradiation quenched the emission intensity excited at 280 nm, indicating changes in the tertiary structure of the enzyme. This study clearly shows that γ-irradiation below 10 kGy can significantly alter the molecular properties and inactivation of the enzyme.
展开▼
