STUDIES ON PLASMA MEMBRANES .I. CHEMICAL COMPOSITION + ENZYME CONTENT OF PLASMA MEMBRANES ISOLATED FROM RAT LIVER
STUDIES ON PLASMA MEMBRANES .I. CHEMICAL COMPOSITION + ENZYME CONTENT OF PLASMA MEMBRANES ISOLATED FROM RAT LIVER
复制标题
DOI：
10.1016/0304-4165(64)90125-4
复制
发表时间：
1964-01-01
期刊：
影响因子：
--
通讯作者：
BENEDETTI, EL
中科院分区：
文献类型：
--
作者：
EMMELOT, P;RUMKE, P;BENEDETTI, EL
从大鼠肝脏分离质膜。电子显微镜显示，这些制剂没有受到其他可识别的细胞成分的污染。针对分离的膜制备的抗体优先被肝组织的质膜固定。在化学上，质膜由磷脂糖蛋白核心组成，主要由摩尔组分组成。重量约为10,000，其上附着着盐溶蛋白。后者在中性pH下带正电，含有四种具有抗原性的蛋白质。分离质膜中的蛋白质、胆碱、磷脂-P、胆固醇、己糖、己糖胺、唾液酸和硫基的含量几乎完全由磷脂P组成，其次是芳香酯酶(EC 3.1.1.2)、NADH2-细胞色素C还原酶(EC 1.6.2.1)和微量NAD核苷酶(EC 3.2.2.5)。碱性和酸性磷酸单酯酶(EC 3.1.3.1和EC 3.1.3.2)，磷酸二酯酶(EC 3.1.3.2)，核糖核酸酶(S)(EC 2.7.7.16)，葡萄糖-6-磷酸酶(EC 3.1.3.9)，NAD焦磷酸酶(EC 3.6.1.9)，镁离子-三磷酸腺苷酶(EC 3.6.1.4)，Na+-K+-镁2+-三磷酸腺苷酶，5[图像]-单核苷酸酶(EC 3.1.3.5)和微量ADPase(EC 3.6.1.6)。这些酶的比活性比微粒体制剂中的相应酶要低或高得多。讨论了质膜制剂被微粒体元素污染的可能性，并根据现有证据得出结论，没有理由认为是这种情况。
Plasma membranes were isolated from rat liver. Electron microscopy showed that the preparations were not contaminated by other identifiable cellular components. Antibodies prepared against the isolated membranes were preferentially fixed by the plasma membranes of liver tissue. Chemically the plasma membranes consisted of a phospholipoglyco-protein core, mainly composed of components of a mol. wt. of about 10,000, to which saline-soluble proteins were attached. The latter were positively charged at neutral pH and contained four antigenically-active proteins. The protein, choline, phospholipid-P, cholesterol, hexose, hexosamine, sialic acid and sulphydryl content of the isolated membranes was measured and expressed in relation to the membrane -bound P, which consisted virtually completely of phospholipid P. Next to arylesterase (EC 3.1.1.2), NADH2-cytochrome c reductase (EC 1.6.2.1) and a trace of NAD nucleosidase (EC 3.2.2.5) activity, the enzymes found present in the isolated plasma membranes were of phosphate-ester-splitting types, viz., alkaline and acid phospho-monoesterases (EC 3.1.3.1 and EC 3.1.3.2), phosphodiesterase (EC 3.1.3.2), ribonuclease(s) (EC 2.7.7.16), glucose-6-phosphatase (EC 3.1.3.9), NAD pyrophosphatase (EC 3.6.1.9), Mg2+-ATPase (EC 3.6.1.4), Na+-K+-Mg2+-ATPase, 5[image]-mononucleotidase (EC 3.1.3.5) and a trace of ADPase (EC 3.6.1.6). The specific activities of these enzymes were either much lower or much higher than those of the corresponding enzymes found in microsomal preparations. The possibility that the plasma-membrane preparations were contaminated by microsomal elements is discussed, and, on account of the available evidence, the conclusion is reached that there is no reason to assume that this was the case.