Mayer R J, Marshall L A
Medicinal Chemistry, SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania 19406.
FASEB J. 1993 Feb 1;7(2):339-48. doi: 10.1096/fasebj.7.2.8440410.
With the recent discoveries of novel forms of phospholipases A2 (PLA2s),2 new schemes for the roles of various PLA2s in lipid metabolism must be considered. The type II 14-kDa PLA2 isolated from human synovial fluid or platelet has many of the biochemical characteristics of the homologous snake venom and mammalian pancreatic PLA2s. It appears to function both as a cell-associated enzyme and extracellularly, where its expression and/or release is regulated by a variety of mediators such as cytokines or growth factors. The mammalian 85-kDa PLA2 purified from monocytic cells or platelets has no sequence homology to the 14-kDa PLA2 and exhibits biochemically different characteristics. It translocates from cytosol to particulate cell fractions in the presence of submicromolar levels of Ca2+ and has a substrate preference for sn-2-arachidonoyl-containing phospholipids. The cellular function and relative importance of these two enzymes in lipid metabolism remain to be determined. In this review, the biochemistry, localization, function, and regulation of these two distinct mammalian Ca(2+)-dependent PLA2 are compared.
随着最近新型磷脂酶A2（PLA2s）的发现，必须考虑各种PLA2在脂质代谢中作用的新方案。从人滑液或血小板中分离出的II型14-kDa PLA2具有许多同源蛇毒和哺乳动物胰腺PLA2的生化特性。它似乎既作为细胞相关酶发挥作用，也在细胞外发挥作用，其表达和/或释放受多种介质如细胞因子或生长因子的调节。从单核细胞或血小板中纯化的哺乳动物85-kDa PLA2与14-kDa PLA2没有序列同源性，并且表现出不同的生化特性。在亚微摩尔水平的Ca2+存在下，它从胞质溶胶转运到颗粒细胞组分，并且对含sn-2-花生四烯酰基的磷脂具有底物偏好。这两种酶在脂质代谢中的细胞功能和相对重要性仍有待确定。在本综述中，比较了这两种不同的哺乳动物Ca(2+)依赖性PLA2的生物化学、定位、功能和调节。
