Effect of different physical states of phospholipid substrates on partially purified platelet phospholipase A2 activity.
Effect of different physical states of phospholipid substrates on partially purified platelet phospholipase A2 activity.
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磷脂底物的不同物理状态对部分纯化的血小板磷脂酶 A2 活性的影响。
DOI：
10.1016/0005-2736(79)90130-5
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发表时间：
1979
期刊：
影响因子：
--
通讯作者：
K. Koizumi
中科院分区：
文献类型：
--
作者：
R. Kannagi;K. Koizumi
对兔血小板碱性磷脂酶A2（EC 3.1.1.4）进行了部分纯化，并研究了底物磷脂酰胆碱的不同物理状态对其活性的影响. (1)从兔血小板的颗粒级分中提取后，通过Sephadex凝胶色谱法，然后通过CM-纤维素色谱法，将该酶纯化约1020倍，其分子量约为10000。12 000，通过凝胶色谱法测定。(2)纯化的酶的活性通过添加洗涤剂而增强。脱氧胆酸钠和胆酸钠显着刺激的活动，这些物质的效果观察远低于临界胶束浓度。Triton X-100对活性有中等程度的刺激作用，且只有在临界胶束浓度以上才有激活作用. (3)在底物卵磷脂中加入带负电荷的磷脂可诱导水解反应的适度活化. (4)在底物中加入长链阳离子会抑制酶的活性，而加入长链阴离子则会激活卵磷脂的水解，但不会激活兔血小板总脂提取物中磷脂酰胆碱的水解. (5)二肉豆蔻酰磷脂酰胆碱的水解在底物相变的温度区域增加。胆固醇浓度为20 mol%时，相变效应减弱。
Partial purification of alkaline phospholipase A2(EC 3.1.1.4) from rabbit platelets was carried out and the effect of different physical states of the substrate phosphatidylcholine on the activity was investigated.1.(1) The enzyme was purified about 1020-fold by means of Sephadex gel chromatography after extraction from a particulate fraction of rabbit platelets, followed by CM-cellulose chromatography, and had a molecular weight of approx. 12 000 as determined by gel chromatography.2.(2) The activity of the purified enzyme was enhanced by the addition of detergents. Sodium deoxycholate and sodium cholate markedly stimulated the activity, and the effect of these substances was observed well below the critical micelle concentrations. Triton X-100 stimulated the activity moderately, and the activation was observed only above the critical micelle concentration.3.(3) The addition of negatively charged phospholipids to the substrate egg phosphatidylcholine induced a moderate activation of hydrolysis.4.(4) The addition of long-chain cation to the substrate induced an inhibition of the activity, whereas the addition of long-chain anion activated the hydrolysis of egg phosphatidylcholine, but did not activate the hydrolysis of phosphatidylcholine in the total lipid extract of rabbit platelets.5.(5) Hydrolysis of dimyristoyl phosphatidylcholine increased in the temperature region of the phase transition of the substrate. Addition of cholesterol at the concentration of 20 mol% diminished the effect of phase transition.