Wang R, Dodia C R, Jain M K, Fisher A B
Institute for Environmental Medicine, University of Pennsylvania Medical Center, Philadelphia 19104-6068.
Biochem J. 1994 Nov 15;304 ( Pt 1)(Pt 1):131-7. doi: 10.1042/bj3040131.
Several phospholipase A2 (PLA2) activities have been identified in rat lung homogenate and shown to be important in metabolism of lung phospholipids. One PLA2 activity is Ca(2+)-independent, active in vitro at pH 4, and inhibited by a substrate analogue, 1-hexadecyl-3-trifluoroethylglycero-sn-2-phosphomethanol (MJ33). Purification of this rat lung PLA2 by approx. 550-fold was carried out by sequential column chromatographies using DE-52, Sephacryl-100, heparin-Sepharose, and phenyl-Sepharose columns. The purified activity had an acidic pH optimum, was Ca(2+)-independent, was inhibited by MJ33 in a dose-dependent manner (50% inhibition at 3 mol%), was unaffected by treatment with p-bromophenacyl bromide or mercaptoethanol, and had a unique N-terminal amino acid sequence. The apparent molecular mass was 15 kDa on gel electrophoresis and activity was recovered in part by renaturation of protein from the gel. The properties of this enzyme suggest a new class of PLA2.
在大鼠肺匀浆中已鉴定出几种磷脂酶A2（PLA2）活性，并且已证明其在肺磷脂代谢中很重要。一种PLA2活性不依赖于Ca(2+)，在pH 4时体外具有活性，并被底物类似物1-十六烷基-3-三氟乙基甘油-sn-2-磷酸甲醇（MJ33）抑制。通过使用DE-52、Sephacryl-100、肝素-琼脂糖和苯基-琼脂糖柱的连续柱色谱法对这种大鼠肺PLA2进行了约550倍的纯化。纯化后的活性具有酸性最适pH，不依赖于Ca(2+)，被MJ33以剂量依赖性方式抑制（3 mol%时50%抑制），不受对溴苯甲酰溴或巯基乙醇处理的影响，并且具有独特的N端氨基酸序列。在凝胶电泳上，表观分子量为15 kDa，通过从凝胶中复性蛋白质部分恢复了活性。这种酶的特性表明它是一种新型的PLA2。
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