机械化酰胺分解因子X测定法的优化；反应条件和试剂的影响。

Optimization of a mechanized amidolytic factor-X assay; influence of reaction conditions and reagents.

作者信息

van Wijk E M, Kahlé L H, Wiebosch M, ten Cate J W

出版信息

Clin Chem. 1981 Jun;27(6):918-21.

Abstract

We describe the effect of pH and NaCl concentration on the activation of factor X in plasma by Russell's viper venom and on the amidolytic activity of the activated enzyme towards factor Xa-sensitive chromogenic substrates. An increasing NaCl concentration results in a decrease in the activation rate of factor X by Russell's viper venom, whereas in this step no pH effect is observed. Increasing NaCl concentrations decrease the Km and Vmax for both the factor Xa-sensitive chromogenic substrates, S 2222 and S 2337. Km values were lowest between pH 7.8 and 8.6; Vmax increased with increasing pH. Comparison of NaCl and KCl in the activation step as well as in the amidolytic step shows that the observed effect is specific for Na+, not just an effect of ionic strength. No difference was detected between activation by the crude venom or its purified factor X-activating enzyme. Also, values with the substrates S 2222 or S 2337 were the same in the mechanized amidolytic factor X assay.

摘要

我们描述了pH值和氯化钠浓度对罗素蝰蛇毒激活血浆中X因子的作用，以及活化酶对Xa因子敏感的生色底物的酰胺水解活性的影响。氯化钠浓度的增加导致罗素蝰蛇毒激活X因子的速率降低，而在此步骤中未观察到pH值的影响。氯化钠浓度的增加会降低Xa因子敏感的生色底物S 2222和S 2337的Km值和Vmax值。Km值在pH 7.8至8.6之间最低；Vmax随pH值的升高而增加。在激活步骤以及酰胺水解步骤中对氯化钠和氯化钾的比较表明，观察到的效应是钠离子特有的，而不仅仅是离子强度的影响。粗毒液或其纯化的X因子激活酶在激活方面未检测到差异。此外，在机械化酰胺水解因子X测定中，底物S 2222或S 2337的值相同。