Iyengar R, Mailman D S, Sachs G
Am J Physiol. 1978 Mar;234(3):F247-54. doi: 10.1152/ajprenal.1978.234.3.F247.
Two types of plasma membrane were purified from canine distal renal medulla by the techniques of differential and zonal density-gradient centrifugation followed by free-flow electrophoresis. One group of plasma membranes was identified as basal-laterally derived based on a 30-fold enrichment of Na-K-ATPase, a 20-fold enrichment of vasopressin-stimulated adenylate cyclase, and a 33-fold enrichment of [3H]vasopressin binding sites. The second type of plasma membrane was free of these markers, but had a cholesterol and phospholipid composition similar to them. Alkaline phosphatase also had a similar distribution in the two fractions. This lighter membrane fraction contained a membrane-bound cyclic AMP-dependent protein kinase as well as substrate for this kinase. In addition there was a 26-fold enrichment of specific activity of an anion (SO32-)-activated ATPase which was insensitive to mitochondrial ATPase inhibitor protein, in contrast to the mitochondrial fraction of the tissue. Based on the relative preponderance of collecting duct tissue in the distal medulla and the yield of membrane protein, these membranes are tentatively identified as containing apical membranes of the collecting duct.
采用差速离心和区带密度梯度离心技术，随后进行自由流动电泳，从犬肾远端髓质中纯化出两种类型的质膜。基于钠钾ATP酶富集30倍、加压素刺激的腺苷酸环化酶富集20倍以及[3H]加压素结合位点富集33倍，一组质膜被鉴定为源自基底外侧。第二种类型的质膜不含这些标志物，但其胆固醇和磷脂组成与它们相似。碱性磷酸酶在这两个组分中的分布也相似。这个较轻的膜组分含有一种膜结合的环磷酸腺苷依赖性蛋白激酶以及该激酶的底物。此外，与组织的线粒体部分相比，阴离子（SO32-）激活的ATP酶的比活性富集了26倍，且该酶对线粒体ATP酶抑制蛋白不敏感。基于远端髓质中集合管组织的相对优势以及膜蛋白的产量，这些膜初步被鉴定为含有集合管的顶端膜。
