钾离子依赖性质子外流及脾脏溶酶体去极化

Potassium ion dependent proton efflux and depolarization from spleen lysosomes.

作者信息

Moriyama Y

机构信息

Roche Institute of Molecular Biology, Roche Research Center, Nutley, New Jersey 07110.

出版信息

Biochem Biophys Res Commun. 1988 Oct 14;156(1):211-6. doi: 10.1016/s0006-291x(88)80826-x.

DOI:10.1016/s0006-291x(88)80826-x

PMID:2845971

Abstract

Lysosomes, isolated from various organs, exhibited an acidic interior (approximately equal to pH 5.2) when incubated in a buffer at neutral pH. K+-induced proton efflux was observed in spleen lysosomes, but not in liver or kidney lysosomes. The initial velocity of the proton efflux showed saturation kinetics with Km value of about 15 mM K+. Rb+ and Cs+ have an effect similar to K+, while Na+, Li+ or divalent cations have little or no effect. The properties of the K+ induced proton efflux correlated with the K+-induced depolarization of the lysosomes, suggesting the presence of K+-transport system(s) in lysosomal membranes.

摘要

从各种器官分离得到的溶酶体，在中性pH缓冲液中孵育时呈现酸性内部环境（约等于pH 5.2）。在脾溶酶体中观察到K⁺诱导的质子外流，但在肝或肾溶酶体中未观察到。质子外流的初始速度呈现饱和动力学，Km值约为15 mM K⁺。Rb⁺和Cs⁺具有与K⁺类似的作用，而Na⁺、Li⁺或二价阳离子几乎没有影响。K⁺诱导的质子外流特性与K⁺诱导的溶酶体去极化相关，表明溶酶体膜中存在K⁺转运系统。