
Product Overview
Background
Plasminogen Activator Inhibitor-1 (PAI-1) is a glycoprotein and member of the serine protease inhibitor (serpin) superfamily. PAI-1 is the primary inhibitor of tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA). This inhibition exhibits antiproteolytic properties that can lead to myocardial infarction, thromboembolic disease with elevated levels of PAI-1. Additionally, PAI-1 is thought to play a role in the function of tissue remodeling and tumor metastasis.
Assay Principle
This is an ELISA (Enzyme-Linked Immunosorbent Assay) for the quantitative analysis of PAI-1 levels in biological fluid. This PAI-1 test kit operates on the basis of sandwich ELISA where active PAI-1 complexes with uPA and is quantified with the use of an HRP labeled secondary antibody. The functional or active PAI-1 will bind to the uPA coated on the well of the microtiter plate. The latent and complexed forms of PAI-1 will not bind and are discarded at a later washing step. Next, a PAI-1 primary antibody is added to the wells, binding to the captured PAI-1 on the microtiter plate. HRP conjugated secondary antibody is then added for detection of the active PAI-1. Quantitative test results are obtained by the measure and comparison of the sample and standard absorbance readings.
Product Documents
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决定酶促反应最大速度Vm的因素是什么?是同一底物,尽管加不同种酶,其Vmax都相同吗?可以画曲线图解释一下吗?可是根据米曼氏方程来看又有点矛盾,Km变大,Vmax也需变大,才可使v变大。所以题目所述到底应该怎么理解呢
酶促反应速率跟底物浓度,pH,温度,酶的 浓度等因素有关,当底物浓度足够高时,酶的浓度相对较低,酶只能与一部分底物结合,导致速率有一个最大值.
1,底物DNA上没有该限制酶的识别、切断位点。特别是一些经过重组等处理的DNA,碱基易发生缺失、变化等。
2,限制酶识别位点上的A或C被甲基化。部分限制酶对识别位点中的碱基是否被甲基化比较敏感,从而无法切断该位点。
3,底物不纯。如果底物DNA中有限制酶阻害物质,回影响限制酶的酶切作用。在此种情况下,底物DNA须重新进行精制。
4,限制酶的识别、切断位点在底物DNA的高级构造中所处的位置,对酶切反应也有一定的影响,例如,限制酶NaeI在切断pBR322DNA时,就有着非常难以切断的部位。
5,限制性内切酶本身无活性或低活性

