Fig. 6 Time course of the reduction of NBT and WST during the oxidation of glucose by glucose oxidase. The assay conditions were same as those in Fig. 3. The assay mixture contained 0.1 mM NBT (■), 0.2 mM WST-1 (●) or 0.2 mM WST-8 (○). The absorbance at 438 (WST-1), 460 (WST-8) or 560 nm (NBT) was monitored at 25℃.