Rothman A, Proverbio T, Proverbio F
Centre of Biophysics and Biochemistry, Institute of Scientific Research, Caracas, Venezuela.
Physiol Res. 1996;45(3):205-11.
The inhibitory effect of 2% ethanol (400 mM) in the incubation medium on several characteristics of the Na(+)-ATPase of basolateral plasma membranes from rat kidney proximal tubular cells was investigated. Ethanol did not change the Km of the enzyme for Mg2+, ATP or Na+; it did not change either the optimal pH or temperature values of the incubation medium for the enzyme to act and finally, it did not affect the apparent energy of activation of the enzyme. It was also found that 2% ethanol produced stronger inhibition of the ATPase when it is in an activated or stimulated state, than when it is working at its lower basal level. The presented results can be explained by assuming that 2% ethanol in the incubation medium inhibits Na(+)-ATPase activity by affecting the enzyme structure as well as its activating mechanism.
研究了孵育培养基中2%乙醇（400 mM）对大鼠肾近端小管细胞基底外侧质膜Na(+)-ATP酶若干特性的抑制作用。乙醇并未改变该酶对Mg2+、ATP或Na+的Km值；它既未改变孵育培养基中该酶发挥作用的最佳pH值或温度值，最后，它也不影响该酶的表观活化能。还发现，2%乙醇在ATP酶处于活化或刺激状态时比其处于较低基础水平时对ATP酶产生更强的抑制作用。所呈现的结果可以通过假设孵育培养基中的2%乙醇通过影响酶结构及其激活机制来抑制Na(+)-ATP酶活性来解释。
