Alterations in individual molecular species of human platelet phospholipids during thrombin stimulation: Electrospray ionization mass spectrometry-facilitated identification of the boundary conditions for the magnitude and selectivity of thrombin-induced platelet phospholipid hydrolysis
Alterations in individual molecular species of human platelet phospholipids during thrombin stimulation: Electrospray ionization mass spectrometry-facilitated identification of the boundary conditions for the magnitude and selectivity of thrombin-induced platelet phospholipid hydrolysis
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DOI：
10.1021/bi952927v
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发表时间：
1996-05-07
期刊：
影响因子：
2.9
通讯作者：
Gross, RW
中科院分区：
文献类型：
--
作者：
Han, XL;GubitosiKlug, RA;Gross, RW
尽管凝血酶诱导的花生四烯酸在人血小板中的快速释放已经被知道超过20年，但花生四烯酸质量动员的量和释放的花生四烯酸的来源仍然是激烈争论的主题。在本文中，我们利用电喷雾电离质谱的分析能力和灵敏度来鉴定血浆乙醇胺作为凝血酶刺激期间释放的花生四烯酸质量的最大来源，并证明人血小板中存在多种新颖的血浆乙醇胺分子种类。凝血酶刺激后90 s，总共60.1 nmol含花生四烯酸的磷脂/10（9）血小板被水解，其中包括31.8 nmol/10（9）血小板的损失。来自乙醇胺甘油磷脂的血小板（血浆乙醇胺的水解占乙醇胺甘油磷脂池损失的63%），但来自胆碱甘油磷脂的血小板仅为10.9nmol/10（9）。人血小板磷脂酰丝氨酸和磷脂酰肌醇池在静息血小板中含有相似量的花生四烯酸物质（约20 nmol/10（9）血小板），并且在凝血酶刺激后每个池贡献8.7 nmol/10（9）血小板。从这些结果，人血小板中凝血酶诱导的花生四烯酸动员速率的下限可设定为>60 nmol/10（9）血小板，从而鉴定在血小板刺激期间活化的磷脂酶的特定动力学特征和底物选择性。总的来说，这些结果强调了血浆乙醇胺作为静息血小板中花生四烯酸的主要储存库和作为凝血酶刺激人血小板后花生四烯酸动员的主要来源的重要性。
Although the rapid thrombin-induced release of arachidonic acid in human platelets has been known for over 20 years, the amount of arachidonic acid mass mobilized and the source of the released arachidonic acid has remained a subject of intense controversy. Herein, we exploit the analytic power and sensitivity of electrospray ionization mass spectrometry to identify plasmenylethanolamines as the largest source of arachidonic acid mass released during thrombin stimulation and to demonstrate the presence of multiple novel molecular species of plasmenylethanolamines in human platelets, Specifically, 90 s after thrombin stimulation a total of 60.1 nmol of arachidonic acid-containing phospholipids/10(9) platelets was hydrolyzed which included the loss of 31.8 nmol/10(9) platelets from ethanolamine glycerophospholipids (hydrolysis of plasmenylethanolamines represented 63% of the mass lost from the ethanolamine glycerophospholipid pool) but only 10.9 nmol/10(9) platelets from choline glycerophospholipids. Human platelet phosphatidylserine and phosphatidylinositol pools contained similar amounts of arachidonic acid mass in resting platelets (approximate to 20 nmol/10(9) platelets), and each pool contributed 8.7 nmol/10(9) platelets after thrombin stimulation, From these results, a lower boundary for the rate of thrombin-induced arachidonic acid mobilization in human platelets can be set at >60 nmol/10(9) platelets, thereby identifying specific kinetic characteristics and substrate selectivities of the phospholipase(s) activated during platelet stimulation. Collectively, these results underscore the importance of plasmenylethanolamines as the major storage depot of arachidonic acid in resting platelets and as the major source of arachidonic acid mobilized after thrombin stimulation of human platelets.