ANALYTICAL STUDY OF MICROSOMES AND ISOLATED SUBCELLULAR MEMBRANES FROM RAT LIVER
ANALYTICAL STUDY OF MICROSOMES AND ISOLATED SUBCELLULAR MEMBRANES FROM RAT LIVER
复制标题
大鼠肝脏微粒体和分离的亚细胞膜的分析研究
作者：
H. Beaufay;A. Amar‐Costesec;D. Thinès;M. Wibo;M. Robbi;J. Berthet
大鼠肝微粒体组分已在各种类型的线性密度梯度中平衡。收集了15个级分，并测定了27种成分。作为该分析的结果，微粒体组分按照中位密度增加的顺序被分为4组，标记为a、B、c和d。a组包括：单胺氧化酶、半乳糖基转移酶、5 '-核苷酸酶、碱性磷酸二酯酶I、碱性磷酸酶和胆固醇; B组：NADH细胞色素c还原酶、NADPH细胞色素c还原酶、氨基比林脱甲基酶、细胞色素B 5和细胞色素P 450; c组：葡萄糖6-磷酸酶、核苷二磷酸酶、酯酶、β-葡萄糖醛酸糖苷酶和葡萄糖醛酸转移酶; d组：RNA、膜结合核糖体和一些可能吸附在核糖体上的酶：核糖核酸酶、醛缩酶和谷氨酰胺合成酶。通过密度梯度差速离心法分析微粒体组分，进一步将a组分离成比B和c组沉降更慢的组分（单胺氧化酶和半乳糖基转移酶），以及沉降更快的5 '-核苷酸酶、碱性磷酸二酯酶I、碱性磷酸酶和胆固醇（a2组）。微粒体单胺氧化酶至少部分归因于线粒体外膜的分离片段。半乳糖基转移酶属于高尔基复合体。a2组成分与质膜有关。组B和c的成分和RNA属于来源于内质网的微粒体囊泡。后者表现出明显的生物化学异质性，最多占微粒体蛋白的80%，其余部分由携带a组成分的颗粒和一些污染的线粒体、溶酶体和过氧化物酶体组成。注意被称为微粒体亚组分的操作意义和它们的细胞学的复杂性。
Rat liver microsomal fractions have been equilibrated in various types of linear density gradients. 15 fractions were collected and assayed for 27 constituents. As a result of this analysis microsomal constituents have been classified, in the order of increasing median density, into four groups labeled a, b, c, and d. Group a includes: monoamine oxidase, galactosyltransferase, 5'-nucleotidase, alkaline phosphodiesterase I, alkaline phosphatase, and cholesterol; group b: NADH cytochrome c reductase, NADPH cytochrome c reductase, aminopyrine demethylase, cytochrome b 5, and cytochrome P 450; group c: glucose 6-phosphatase, nucleoside diphosphatase, esterase, β-glucuronidase, and glucuronyltransferase; group d: RNA, membrane-bound ribosomes, and some enzymes probably adsorbed on ribosomes: fumarase, aldolase, and glutamine synthetase. Analysis of the microsomal fraction by differential centrifugation in density gradient has further dissociated group a into constituents which sediment more slowly (monoamine oxidase and galactosyltransferase) than those of groups b and c, and 5'-nucleotidase, alkaline phosphodiesterase I, alkaline phosphatase, and the bulk of cholesterol which sediment more rapidly (group a2). The microsomal monoamine oxidase is attributed, at least partially, to detached fragments of external mitochondrial membrane. Galactosyltransferase belongs to the Golgi complex. Group a2 constituents are related to plasma membranes. Constituents of groups b and c and RNA belong to microsomal vesicles derived from the endoplasmic reticulum. These latter exhibit a noticeable biochemical heterogeneity and represent at the most 80% of microsomal protein, the rest being accounted for by particles bearing the constituents of groups a and some contaminating mitochondria, lysosomes, and peroxisomes. Attention is called to the operational meaning of microsomal subfractions and to their cytological complexity.