Kim D K, Lee H J, Lee Y
Department of Life Science, Pohang Institute of Science and Technology, Korea.
FEBS Lett. 1994 May 2;343(3):213-8. doi: 10.1016/0014-5793(94)80558-x.
Leaves of higher plant Vicia faba contains two Phospholipase A2 (PLA2) activities which are detected in cytosolic fractions. Based on a gel filtration column chromatography, two cytosolic PLA2 activities migrated with molecular masses of 70 kDa and 14 kDa. The first (70 kDa peak) was optimally active at pH 4.5 and was not dependent on [Ca2+] for its activity. In the presence of 5 mM CaCl2, 'phospholipase B' activity was shown in the 70 kDa peak. The second (14 kDa peak) was optimally active in the pH range 9-10 and required millimolar concentrations of calcium for optimal activity. The two activities were not inhibited by dithiothreitol. Neither anti-pancreatic PLA2 antiserum nor anti-(pig spleen 100 kDa cytosolic PLA2) antiserum immunoprecipitated any activity of the two plant PLA2's. The present results indicate that at least the 14 kDa form of the two PLA2 enzymes detected in leaves of higher plants is biochemically and immunochemically different from the well characterized Ca(2+)-dependent mammalian PLA2's.
高等植物蚕豆的叶子含有两种磷脂酶A2（PLA2）活性，可在胞质部分检测到。基于凝胶过滤柱色谱法，两种胞质PLA2活性的迁移分子量分别为70 kDa和14 kDa。第一种（70 kDa峰）在pH 4.5时活性最佳，其活性不依赖于[Ca2+]。在存在5 mM CaCl2的情况下，70 kDa峰显示出“磷脂酶B”活性。第二种（14 kDa峰）在pH 9 - 10范围内活性最佳，需要毫摩尔浓度的钙才能达到最佳活性。这两种活性均不受二硫苏糖醇的抑制。抗胰腺PLA2抗血清和抗（猪脾脏100 kDa胞质PLA2）抗血清均未免疫沉淀这两种植物PLA2的任何活性。目前的结果表明，至少在高等植物叶子中检测到的两种PLA2酶的14 kDa形式在生化和免疫化学上与已充分表征的Ca(2+)依赖性哺乳动物PLA2不同。
