A substrate specificity of cabbage phospholipase D (PLD) was studied using the synthetic phospholipids having different head groups. The phospholipids were synthesized from phosphatidylcholine and appropriate bases by transphosphatidylation of PLD. The bases used were ethanolamine, serine, ethanol and ャ -hydroxybutyric acid. The phosphatidic acid, the product of PLD, was separated in TLC and measured densitometrically. The kinetic parameters were estimated for each substrate and the effects of pH, SDS, Ca2+ and other metal ions were examined. Vmax values found were 3.75, 2.36, 5.59, 1.63, 2.30 nmol/min/レg protein for phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylethanol, and phosphatidylburytic acid, respectively. These results indicate a broad specificity of cabbage PLD toward phospholipids with different head groups. Particularly phosphatidylserine was most easily hydrolyzed by PLD and its activity did not depend on Ca2+.
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机译:使用具有不同头部基团的合成磷脂研究了卷心菜磷脂酶 D (PLD) 的底物特异性。磷脂由磷脂酰胆碱和适当的碱基通过PLD的转磷脂酰化合成。使用的碱是乙醇胺、丝氨酸、乙醇和ャ-羟基丁酸。PLD的产物磷脂酸在TLC中分离并进行密度测量。估计了每种基底的动力学参数,并检查了pH、SDS、Ca2+和其他金属离子的影响。磷脂酰胆碱、磷脂酰乙醇胺、磷脂酰丝氨酸、磷脂酰乙醇和磷脂酰伯里酸的Vmax值分别为3.75、2.36、5.59、1.63、2.30 nmol/min/レg蛋白。这些结果表明,卷心菜PLD对具有不同头部群的磷脂具有广泛的特异性。特别是磷脂酰丝氨酸最容易被PLD水解,其活性不依赖于Ca2+。
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