The enzymatic composition of rat liver microsomes during liver regeneration.
The enzymatic composition of rat liver microsomes during liver regeneration.
复制标题
肝再生过程中大鼠肝微粒体的酶组成。
DOI：
10.1016/0014-4827(60)90066-5
复制
发表时间：
1960
影响因子：
3.7
通讯作者：
Tore Hultin
中科院分区：
文献类型：
--
作者：
A. Decken;Tore Hultin
从正常大鼠肝脏和部分肝切除后的肝脏平行制备微粒体悬浮液。在相同蛋白质含量的基础上比较了再生周期中不同酶的活性，生长诱导对葡萄糖-6-磷酸酶活性的影响有限，DPNH-和TPNH细胞色素还原酶以及DPNH-和TPNH黄递酶。另一方面，MAB的氧化去甲基化活性在约12- 200 μ g/ml的滞后期后迅速下降。14小时。在肝微粒体的存在下，致癌胺与蛋白质结合。需要与代谢氧化相同的条件。在不同的系统中研究了标记致癌胺的同位素与蛋白质的结合：（a）用TPNH-产生系统强化的无α-淀粉酶的匀浆，（B）与TPNH-产生系统组合的分离微粒体，（c）加入TPNH的分离微粒体。在所有这些系统中的微粒体的活性，以实现结合的同位素的蛋白质表现出显着的下降，在肝regeneration.In一些实验中的渗出液从微粒体的反应性代谢物的标记胺分别测量通过添加，可溶性受体蛋白，其中被分离后再次孵育。再生过程中，同位素与这些蛋白质的结合也有所减少，但不如与微粒体蛋白质的结合那么多。本文讨论了其原因，并测定了一些微粒体制备物中细胞色素b_5的含量。在再生肝脏的微粒体中观察到显著降低。
Microsomal suspensions were prepared in parallel from normal rat livers and from livers after partial hepatectomy. The activities of different enzymes were compared in the course of the regeneration cycle on the basis of equal protein content.The growth induction had only limited effects on the activities of glucose-6-phosphatase, DPNH- and TPNH cytochromecreductases and DPNH- and TPNH diaphorases.The activity of oxidative demethylation of MAB on the other hand rapidly decreased after a lag period of about 12–14 hours.In the presence of liver microsomes carcinogenic amines become bound to proteins. The same conditions as for metabolic oxidation are required. The binding to proteins of isotope from labeled carcinogenic amines was studied in different systems: (a) mitochondria-free homogenates fortified with a TPNH-generating system, (b) isolated microsomes combined with a TPNH-generating system, (c) isolated microsomes in the presence of added TPNH. In all of these systems the activity of the microsomes to effect a binding of isotope to proteins showed a marked decrease during the liver regeneration.In some experiments the effusion from the microsomes of reactive metabolites of the labeled amines was measured separately by means of added, soluble acceptor proteins which were isolated again after the incubation. The binding of isotope to these proteins also decreased during regeneration, but not quite as much as the binding to the microsomal proteins. The reasons for this are discussed.The content of cytochromeb5was determined in a number of the microsomal preparations. In the microsomes from regenerating livers a pronounced decrease was observed.