Canestrari F, Galli F, Boschi S, Albertini M C, Gheller G, De Crescentini S, Bossú M
Institute of Biological Chemistry G. Fornaini, University of Urbino, Italy.
Clin Chim Acta. 1994 Jan 31;224(2):167-79. doi: 10.1016/0009-8981(94)90183-x.
The activity and some kinetic properties of RBC Na+,K(+)-ATPase (EC 3.6.1.37) were investigated in essential hypertensives (EH; 40 subjects) and normotensives (NT; 20 subjects). A decrease in ouabain-sensitive 86Rb uptake as well as ouabain-sensitive ATPase activity was found in EH. [Na+]i and [K+]i of EH did not show any statistical difference from NT. Na+,K(+)-ATPase showed a reduced Mg2+ activation and the apparent Km value for Mg2+ was 2-fold increased in the EH group. The influence of temperature on the Na+,K(+)-ATPase showed a reduced modulation and a minor activity peak at 37 degrees C in the patients, consequently the calculated activation energy of the enzyme was increased at temperatures lower than 40 degrees C. Increased RBC adenylate energy charge (EC) was observed in EH when compared with NT. A negative correlation between EC and total Na+,K(+)-ATPase activity was found when all subjects were compared and also in both groups, showing a possible pump involvement in the regulation of the RBC metabolic flux in EH. These data provide evidence about some modifications in active Na+,K+ transport and in EC in RBC which allows a further characterization of membrane cation fluxes in EH.
在原发性高血压患者（EH，40例）和血压正常者（NT，20例）中研究了红细胞Na⁺,K⁺-ATP酶（EC 3.6.1.37）的活性及一些动力学特性。在EH患者中发现哇巴因敏感的⁸⁶Rb摄取以及哇巴因敏感的ATP酶活性降低。EH患者的细胞内Na⁺浓度（[Na⁺]i）和细胞内K⁺浓度（[K⁺]i）与NT相比无统计学差异。Na⁺,K⁺-ATP酶的Mg²⁺激活作用降低，且EH组中Mg²⁺的表观米氏常数（Km）值增加了2倍。温度对Na⁺,K⁺-ATP酶的影响显示患者在37℃时调节作用降低且活性峰值较小，因此在低于40℃的温度下该酶的计算活化能增加。与NT相比，EH患者的红细胞腺苷酸能荷（EC）增加。当比较所有受试者以及两组时，发现EC与总Na⁺,K⁺-ATP酶活性之间呈负相关，这表明在EH中可能存在泵参与红细胞代谢通量的调节。这些数据为红细胞中主动Na⁺,K⁺转运和EC的一些改变提供了证据，这有助于进一步表征EH中的膜阳离子通量。
