van Os C H, Mircheff A K, Wright E M
J Cell Biol. 1977 Apr;73(1):257-60. doi: 10.1083/jcb.73.1.257.
This study reports on the distribution of bicarbonate-stimulated ATPase in rat intestinal epithelial cells. Brush-border membranes and basolateral membranes were separated from each other and from mitochondrial and other intracellular membranes by differential and density gradient centrifugation. Bicarbonate-sensitive ATPase activity followed the mitochondrial marker succinic dehydrogenase closely throughout all the centrifugation steps. The low HCO3--ATPase activity in purified brush-border and basolateral plasma membranes could be accounted for quantitatively by the small mitochondrial contamination. Consequently, there are no grounds for postulating that this enzyme has a direct role in H+ or HCO3- transport across the rat small intestine.
本研究报道了大鼠肠上皮细胞中碳酸氢盐刺激的ATP酶的分布情况。通过差速离心和密度梯度离心,将刷状缘膜和基底外侧膜彼此分离,并与线粒体膜及其他细胞内膜分离。在整个离心步骤中,对碳酸氢盐敏感的ATP酶活性与线粒体标志物琥珀酸脱氢酶的活性密切相关。纯化的刷状缘膜和基底外侧质膜中低HCO3--ATP酶活性可通过少量线粒体污染进行定量解释。因此,没有理由假定该酶在H+或HCO3-跨大鼠小肠转运中具有直接作用。