大鼠钠泵α2亚单位M1-M2膜外区多肽体外活性鉴定  

Activity identification of peptide containing rat sodium pump α2 subunit M1-M2 extramembrane fragment in vitro

作　　者：张明娟[1] 杨军[1] 强磊[1] 王蓉[1] 宋亚燔[1] 牛小麟[1] 

机构地区：[1]西安交通大学医学院第二附属医院心内科,西安710004

出　　处：《生理学报》2008年第2期205-210,共6页Acta Physiologica Sinica

基　　金：the National Natural Science Foundation of China(No.30500204)

摘　　要：本文旨在研究含大鼠钠泵α2亚单位M1-M2膜外区的多肽片段（peptide containing rat sodium pumpα2subunit M1-M2extramembrane fragment,RES2衍生物）是否具有与内源性钠泵抑制因子结合以及改善钠泵α亚单位活性的作用。采用Fmoc固相合成法合成多肽（Leu-Ala-Ala-Met-Glu-Asp-Glu-Pro-Ser-Asn-Asp-Asn-Gly-Gly-Gly-Ser）,产物经高效液相色谱技术纯化,并进行质谱分析。采用放射性配体-受体结合法检测其与哇巴因的结合能力,进而采用人红细胞86Rb摄取实验检测其生物学活性。结果显示,RES2衍生物与3H-哇巴因具有一定的结合能力,其平衡解离常数（Kd）为38.46nmol/L,IC50为6.353nmol/L。RES2衍生物可以阻断哇巴因对红细胞膜Na＋,K＋-ATPase的抑制作用,使红细胞86Rb摄取率从38.53%上升到83.69%左右,并呈一定的剂量依赖关系。因此,RES2衍生物不仅具有体外结合活性,而且具有改善钠泵活性的生物学效应,为其成为有效的抗高血压药物提供科学依据。In order to explore the activity of a peptide containing rat sodium pump α2 subunit M1-M2 extramembrane fragment （RES2 derivative） in vitro, the peptide （Leu-Ala-Ala-Met-Glu-Asp-Glu-Pro-Ser-Asn-Asp-Asn-Gly-Gly-Gly-Ser） was synthesized by peptide synthesizer with Fmoc method and purified by high performance liquid chromatography （HPLC）. Its binding activity was identified by radioligand-receptor binding assay （RRA） and its bioactivity was measured by erythrocyte ^86Rb uptake. The results of saturation binding experiment and competitive binding experiment showed that the synthesized RES2 derivative had the capability to bind to ^3H-ouabain. The dissociation constant （Kd） was 38.46 nmol/L and IC50 was 6.353 nmol/L. Erythrocyte ^86Rb uptake experiment showed that the RES2 derivative blocked the inhibitory effect of ouabain on the sodium pump on erythrocyte membrane in a dosedependent manner. The results showed that the RES2 derivative is capable of binding to ouabain and improving the activity of sodium pump on erythrocyte membrane, suggesting that the RES2 derivative might become an effective antihypertensive drug in the future.

关 键 词：钠泵α2亚单位 膜外区 哇巴因 高血压 

分 类 号：R544.1[医药卫生—心血管疾病]