斑节对虾鳃Na^+/K^+-ATPase的活性

Activity of Na^+/K^+-ATPase from the gill of the giant tiger shrimp (Penaeus monodon)

研究了培养介质的Na+ 、K+ 和Mg2 + 浓度、Na+ ∶K+ 比、pH值、培养温度以及培养时间和底物ATP -Na2量对斑节对虾鳃Na+ /K+ ATPase活性的影响。培养介质中Na+ 浓度为 5 0～ 10 0mM、K+ 浓度为 2 5～ 30mM、Mg2 + 浓度为 8～ 2 0mM、Na+ ∶K+ 比在 10∶1～ 2∶1、pH 7.0～ 7.5时 ,Na+ /K+ ATPase活性较高 ,Na+ /K+ ATPase活性随着培养温度升高而增大。Na+ /K+ ATPase反应时释放出的无机磷 (Pi)累积量与培养时间呈直线性增加。底物ATP Na2 浓度达到 1.0 4mM时 ,Na+ /K+ ATPase活性达到最高 ,随着ATP Na2 量的增多 ,Na+ /K+

The sodium potassium dependent adenosine triphosphatase (Na +/K + ATPase) is assumed to be a key enzyme in adaptive process in euryhaline aquatic organisms. This paper demonstrated activity of Na +/K + ATPase in branchial preparations from the giant tiger shrimp (Penaeus monodon), examined the ion and substrate requirements and effects of incubation temperature, pH and incubation time. Maximal enzyme activity was obtained at 50 to 100 mM Na +, 25 to 30mM K +, 8 to 20mM Mg 2+ , Na∶K ratio of 2∶1, and pH at 7.0 to 7.5. The activity of Na +/K + ATPase increased with the increasing of incubation temperature. The increasing of incubation time resulted in a close to linear release of phosphate from the substrates catalysed by Na +/K + ATPase. Maximal activity of Na +/K + ATPase was gained at 1.0mM ATP Na 2 ,while activity of Na +/K + ATPase was not promoted with higher concentration of ATP Na 2.