Abstract
The distribution and degradation of β-D-glucose oxidase (from Penicillium amagasa-kiense) intravenously injected into rats and mice are described in detail. The uptake of intravenously injected β-D-glucose oxidase (0.45 mg/kg) by various tissues of rats and mice was followed over a period of 60 hr by determining the enzyme activity with the polarographic oxygen electrode. The highest activity of the tracer enzyme injected into rats was found in the liver. Considerable amount was taken up by the spleen. The activity in the liver and spleen reached a maximum in 1-2 and 4-6 hr, respectively. Any activity was not found in other tissues 40 min after the injection. Activity in blood also disappeared in 40 min and that in the liver and spleen almost entirely disappeared in 60 hr. Only slight differences in the distribution of the enzyme were observed between rats and mice. β-D-Glucose oxidase in the liver of rats and mice was histochemically detected only in the Kupffer cells, but not in the parenchymal cells. The enzyme degradation studies in vitro suggested that the enzyme taken up by the Kupffer cells may be concertedly inactivated by the hydrolytic enzymes in lysosomes of the Kupffer cells and by the pH elevation (above 7.4) in the cell fluid.
