Heterogeneity of brush-border-membrane vesicles from rat small intestine prepared by a precipitation method using Mg/EGTA.
Heterogeneity of brush-border-membrane vesicles from rat small intestine prepared by a precipitation method using Mg/EGTA.
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使用 Mg/EGTA 通过沉淀法制备的大鼠小肠刷状缘膜囊泡的异质性。
DOI：
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发表时间：
1983
期刊：
影响因子：
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通讯作者：
H. Murer
中科院分区：
文献类型：
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作者：
B. Stieger;H. Murer
采用MG/EGTA沉淀法分离大鼠小肠刷状缘膜囊泡。通过自由流动电泳法或蔗糖密度梯度离心法进一步分级，得到的亚组分在酶浓缩因子、D-葡萄糖的运输性质和十二烷基硫酸钠/聚丙烯酰胺凝胶电泳法分析的蛋白质图谱方面有所不同。其中一个组分的(Na++K+)-ATPase相对丰富，而另一个组分的麦芽糖酶、氨基肽酶M和碱性磷酸酶相对丰富。这些组分在示踪剂交换条件下表现出不同的D-葡萄糖转运特性，并且根茎苷和根茎维甲素对D-葡萄糖转运有不同的抑制作用。这些结果表明，用阳离子沉淀法从大鼠小肠获得的囊泡是不均匀的。这种不均一性不可能是由于细胞膜以外的膜的交叉污染，因为没有一个组分显示明显富含琥珀酸--细胞色素c氧化还原酶、抗KCN的NADH氧化还原酶或氨基葡萄糖苷酶。这种不均质性可能是由于基底膜-侧膜的交叉污染，也可能是由于来自尚未完全分化的上皮细胞的膜。
Brush border membrane vesicles from rat small intestine were isolated by a Mg/EGTA precipitation method. Further fractionation either by free flow electrophoresis or by sucrose density gradient centrifugation leads to subfractions which differ with respect to enzyme enrichment factors, transport properties for D-glucose and protein pattern analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. A relative enrichment of (Na+ + K+)-ATPase is found in one fraction, whereas in another fraction maltase, aminopeptidase M and alkaline phosphatase are relatively enriched. The fractions show different properties of D-glucose transport under tracer exchange conditions and a different inhibition of D-glucose transport by phlorizin and phloretin. These results indicate that the vesicles obtained from rat small intestine by this cation precipitation method are not homogeneous. The inhomogeneity cannot be due to a crosscontamination by membranes other than from the cell envelopment, as none of the fractions show a significant enrichment of succinate--cytochrome c oxidoreductase, KCN-resistant NADH oxidoreductase or glucosaminidase. The inhomogeneity might be due either to a crosscontamination by basal-lateral membranes or to membranes derived from epithelial cells not yet fully differentiated.