A proposed reference method for plasminogen activators that enables calculation of enzyme activities in S1 units
A proposed reference method for plasminogen activators that enables calculation of enzyme activities in S1 units
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DOI：
10.1111/j.1538-7836.2004.00816.x
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发表时间：
2004-08-01
影响因子：
10.4
通讯作者：
Whitton, CM
中科院分区：
文献类型：
--
作者：
Longstaff, C;Whitton, CM
已经开发了一种用于准确和精确地测量用作血栓溶解剂的一系列纤溶酶原激活剂（PA）的活性的方法，所述纤溶酶原激活剂包括链激酶、组织纤溶酶原激活剂（tPA）和变体以及尿激酶（uPA），单链和双链形式。纤溶酶原活化在透明的固体纤维蛋白基质中监测，但使用发色底物水解而不是纤维蛋白的变化来定量PA的活性。该方法已在最近两项涉及tPA和链激酶的国际合作研究中进行了测试，结果显示其表现非常好。此外，该方法基于合理的酶学原理，并且一旦对纤维蛋白（原）的竞争性抑制进行校正，纤溶酶的产生就可以以摩尔计确定，因此PA的活性可以以SI单位（纤溶酶摩尔浓度的增加速率）以及国际单位表示和比较。该测定也以这样的方式进行安排，以反映在溶栓治疗过程中PA在体内的行为，并且表明链激酶和tPA在该系统中的比活性反映了这些溶栓药物在用于治疗心肌梗塞的输注中给予的剂量下的纤溶酶生成能力。该方法可作为PA的一种参考方法，为纤溶酶的研究和模型化提供了一种严格的手段，并有助于第三代溶栓药物的合理设计。
A method has been developed for accurately and precisely measuring the activity of a range of plasminogen activators (PAs) used as thrombolytic agents, including streptokinase, tissue plasminogen activator (tPA) and variants, and urokinase (uPA), both single and two chain forms. Plasminogen activation is monitored in a transparent, solid fibrin matrix but uses chromogenic substrate hydrolysis, rather than changes in fibrin, to quantitate the activity of PAs. The method has been tested in two recent international collaborative studies involving tPA and streptokinase where it has been shown to perform very well. Furthermore, the method is based on sound enzymological principles and once correction for the competitive inhibition of fibrin(ogen) is made, the generation of plasmin can be determined in molar terms and hence the activity of PAs can be expressed and compared in SI units (rate of increase in molar concentration of plasmin) as well as International Units. The assay is also arranged in such a way to reflect the behavior of PAs in vivo during thrombolytic therapy and it is shown that the specific activity of streptokinase and tPA in this system reflects plasmin generation capacity of these thrombolytics for doses given in infusions for treatment of myocardial infarction. The method would make a suitable reference method for PAs and provides a rigorous means of studying and modeling the enzymology of fibrinolysis and will be helpful in the rational design of third generation thrombolytic agents.