Inactivation of glucose oxidase by the cationic detergent, hexadecyltrimethylammonium bromide.

Abstract

Glucose oxidase (EC 1.1.3.4) was inactivated almost completely at pH 7.0 (0.1m sodium phosphate buffer, ionic strength = 0.22) by the cationic detergent, hexadecyltrimethylammonium bromide at a molar ratio of HTAB/GOD ≧ 1,700. This inactivation was accompanied by 1) a blue shift in the region of 270~300nm, 2) an increase in FAD fluorescence at 520 nm, and 3) an approximately 3-fold increase in tryptophan fluorescence at 340 nm. The extent of inactivation of glucose oxidase by the cationic detergent was different from that observed with other detergents under the same experimental conditions. When the substrate, D-glucose, was added to the enzyme solution before the addition of hexadecyltrimethylammonium bromide under anaerobic conditions, the activity of glucose oxidase decreased to 70% of its original value after incubation at 25°C for 24 hr. In contrast, an anionic detergent, sodium dodecylsulfate, or a nonionic detergent, Triton X-100, did not produce measurable changes in the enzyme activity.Thus, the...