Krause H, Dieter P, Schulze-Specking A, Ballhorn A, Decker K
Biochemisches Institut, Albert-Ludwigs-Universität Freiburg im Breisgau, Federal Republic of Germany.
Eur J Biochem. 1991 Jul 15;199(2):355-9. doi: 10.1111/j.1432-1033.1991.tb16131.x.
In cell-free extracts of rat liver macrophages (Kupffer cells) phospholipase A2 was found to be rapidly associated with the particulate fraction in a Ca(2+)-dependent manner at Ca2+ concentrations of 0.1-1.0 microM. This is also the range of the levels of intracellular Ca2+ reported for basal and various stimulated conditions. After translocation, phospholipase A2 could be released from the membranes in the presence of Ca2+ chelators, increasing the specific activity of phospholipase A2 in the supernatant fraction. These findings support the view that translocation is a regulatory mechanism of phospholipase A2 by bringing the enzyme to its substrate. Unlike the situation with protein kinase C, Mg2+ exerted little effect on phospholipase A2 translocation, indicating that this process is regulated in vivo mainly by fluctuations of the intracellular Ca2+ content.
在大鼠肝脏巨噬细胞（库普弗细胞）的无细胞提取物中，发现磷脂酶A2在0.1 - 1.0微摩尔的Ca2 +浓度下以Ca(2 +)依赖的方式迅速与颗粒部分结合。这也是报道的基础和各种刺激条件下细胞内Ca2 +水平的范围。转位后，在Ca2 +螯合剂存在的情况下，磷脂酶A2可从膜上释放出来，增加上清液部分中磷脂酶A2的比活性。这些发现支持这样一种观点，即转位是磷脂酶A2的一种调节机制，通过将该酶带到其底物上。与蛋白激酶C的情况不同，Mg2 +对磷脂酶A2转位几乎没有影响，表明该过程在体内主要受细胞内Ca2 +含量波动的调节。
