Gerencser G A
Department of Physiology, College of Medicine, University of Florida, Gainesville 32610.
Am J Physiol. 1990 Dec;259(6 Pt 2):R1111-6. doi: 10.1152/ajpregu.1990.259.6.R1111.
Both a Cl(+)-stimulated adenosinetriphosphatase (ATPase) activity and an ATP-dependent Cl- transport process were found in Aplysia foregut absorptive cell plasma membranes. In an attempt to further characterize this transport process, plasma membrane vesicles from Aplysia foregut absorptive cells were prepared utilizing differential centrifugation and sucrose density-gradient techniques. Sulfhydryl ligand participation in ATP-dependent Cl- transport was confirmed in three ways. First, 1,4-dithiothreitol partially restored a p-chloromercurobenzene sulfonate (PCMBS)-inhibited ATP-dependent Cl- transport. Second, 1,4-dithiothreitol restored intravesicular negativity inhibited by PCMBS. Third, 1,4-dithiothreitol had no effect on either ATP-dependent Cl- transport or ATP-dependent intravesicular negativity inhibited by N-ethylmaleimide. These results are consistent with the hypothesis that surface sulfhydryl groups participate in the functioning of the active electrogenic Cl- transport mechanism in Aplysia gut.
在海兔前肠吸收细胞质膜中发现了一种氯离子刺激的三磷酸腺苷酶（ATP酶）活性以及一种依赖ATP的氯离子转运过程。为了进一步表征这种转运过程，利用差速离心和蔗糖密度梯度技术制备了海兔前肠吸收细胞质膜囊泡。巯基配体参与依赖ATP的氯离子转运通过三种方式得到证实。首先，1,4-二硫苏糖醇部分恢复了对氯汞苯磺酸盐（PCMBS）抑制的依赖ATP的氯离子转运。其次，1,4-二硫苏糖醇恢复了被PCMBS抑制的囊泡内负电位。第三，1,4-二硫苏糖醇对被N-乙基马来酰亚胺抑制的依赖ATP的氯离子转运或依赖ATP的囊泡内负电位均无影响。这些结果与表面巯基参与海兔肠道中活性生电氯离子转运机制功能的假说一致。
