| Effects of Ethanol on Na-K-ATPase Activity of Cat Kidney |
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Joo-Heon Kim1, Yong-Keun Kim2 |
1Department of Veterinary Medicine, College of Agriculture, Gyeongsang National University
2Department of Physiology, College of Medicine, Busan National University |
| Ethanol 이 고양이 신장 Na-K-ATPase 활성에 미치는 영향 |
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김주헌1, 김용근2 |
1경상대학교 농과대학
2부산대학교 의과대학 생리학교실 |
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| Abstract |
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The effects of ethanol on Na-K-ATPase activity were investigated with cat kidney homogenate. The results were summarized as follows: 1. Na-K-ATPase activity was inhibited with dose-dependent manner by ethanol of higher concentration than 1%, and showed an estimated $I_{50}$ (the inhibitor concentration to cause 50% inhibition) of 7.5%. 2. Hydrolysis of ATP was linear with the incubation time in the absence and presence of 8% ethanol, whereas it was different with preincubation time in the presence of 15% ethanol. 3. Inhibition of Na-K-ATPase activity by ethanol was not affected by increased enzyme concentration, and showed the reversibility of the inhibitory pattern. 4. Kinetic studies of cationic-substrate activation of Na-K-ATPase showed that ethanol had both properties of classical competitive inhibition for $Mg^{{+}{+}}$ or $K^+ and non-competitive inhibition for ATP or $Na^+$. 5. Arrhenius plot yield two break point at $21^{circ}$ and $30^{circ}C$ in the absence of ethanol, whereas showing only one break point at $18^{circ}C$ in the presence of 8% ethanol. These results suggested that ethanol inhibited Na-K-ATPase activity reversible through a disturbance of microenvironment of lipids associated with the enzyme. |
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