Lewis S D, Shafer J A
Thromb Res. 1984 Jul 15;35(2):111-20. doi: 10.1016/0049-3848(84)90206-8.
An assay for thrombin is presented wherein thrombin-catalyzed hydrolysis at Arg-A alpha-16 to release fibrinopeptide A (FPA) from fibrinogen is measured using high-performance liquid chromatography (HPLC). In this assay one thrombin unit (TU) is defined as that amount of thrombin that will release half of the FPA in one min from one ml of a solution of greater than 90% clottable normal human fibrinogen (less than or equal to 0.35 microM) at 37 degrees C, pH 7.4, /2 0.15. One TU is equivalent to approximately 0.1 NIH unit of thrombin and approximately 1 pmol of pure human thrombin. At 37 degrees C, pH 7.4, and plasma levels of fibrinogen of 3 mg/ml, one TU will catalyze the release of 3.6 nmol FPA min-1. Variability in fibrinogen samples which produce dramatic differences in clotting time assays with the same sample of thrombin, produce little or no variation in the catalytic assay for TU. The assay for TU obviates the need for maintenance of a thrombin reference standard.
本文介绍了一种凝血酶测定方法，其中使用高效液相色谱（HPLC）测量凝血酶催化在精氨酸 - Aα - 16处的水解反应，以从纤维蛋白原中释放纤维蛋白肽A（FPA）。在该测定中，一个凝血酶单位（TU）定义为在37℃、pH 7.4、离子强度0.15条件下，一分钟内从1 ml大于90%可凝的正常人纤维蛋白原（≤0.35 microM）溶液中释放一半FPA的凝血酶量。一个TU约相当于0.1 NIH单位的凝血酶和约1 pmol的纯人凝血酶。在37℃、pH 7.4以及纤维蛋白原血浆水平为3 mg/ml时，一个TU将催化每分钟释放3.6 nmol FPA。在相同凝血酶样品的凝血时间测定中会产生显著差异的纤维蛋白原样品，在TU的催化测定中产生的变化很小或没有变化。TU的测定无需维持凝血酶参考标准品。
