악하선에서의 Na⁺, k⁺- activated adenosine triphosphatase의 특성에 관한 실험적 연구

An Experimental Study on Characteristics of Na⁺, K⁺- activated Adenosine Triphosphatase in Submaxillary Gland

The Na-K-ATPase was isolated from cat submaxillary gland by a deoxyclolate-treated procedure. In order to determine the characteristics of Na-K-ATPase of submaxillary gland, effects of incubation time, medium composition, temperature and various drugs were investigated. The results were summarized as fellows: 1. The specific activities of Na-K-ATPase and Mg-ATPase were 0.58±0.04 and 0.42±0.03μmol Pi/㎎ protein/min, respectively, in twice deoxycholate-treated microsome. 2. The initial velocity of the Na-K-ATPase reaction was directly proportional to the incubation time and to the enzyme concentration in the medium. 3. The rate of the reaction was dependent on the concentrations of ATP, Mg, Na, K and H ions in the medium, showing maximal activity at 2mM ATP, 3mM Mg, 100mM Na and 10mM K. 4. The maximal activity of Na-K-ATPase was observed in pH 7.5 but Mg-ATPase activity increased by increasing of medium pH. 5. The Na-K-ATPase activity was inhibited by ouabain and ethacrynic acid, but not affected by NaN₃, acetylcholine and mitomycin-C. 6. The Arrhenius plot showed biphasic pattern and the higher activation energy at lower range(10-25℃) than higher temperature range(25-37℃). These results indicate that the Na-K-ATPase of submaxillary gland of cat is similar to that of the other tissue in its physiological and biochemical properties.