Abstract：
Protein C (PC) is a vitamin K-dependent zymogen synthesized in the liver that plays a major role in regulating the coagulation pathway. Upon interaction with the thrombin-thrombomodulin complex, PC is converted to its active form, activated PC (APC). APC complexes with protein S and regulates thrombin generation by the inactivation of Factors Va and VIIIa. The role of PC as a key regulator of the coagulation process is highlighted in the deficiency state, in which heterozygous deficiency of PC predisposes to an increased risk of venous thromboembolism (VTE), while in the homozygous deficiency state, potentially fatal complications in the fetus including purpura fulminans and disseminated intravascular coagulation (DIC) can occur. Protein C is often measured with other factors such as protein S and antithrombin as a screen in the investigation of VTE. The chromogenic PC assay, the protocol described in this chapter, quantitates the amount of functional PC in the plasma using an activator of PC with the degree of color change proportional to the amount of PC present in the sample. Other methods, including functional clotting-based assays and antigenic assays, are available; however, protocols for these assays will not be provided in this chapter.
摘要：
蛋白C（PC）是在肝脏中合成的维生素K依赖性酶原，在调节凝血途径中起主要作用。在与凝血酶-血栓调节蛋白复合物相互作用时，PC转换为其活动形式，激活PC（APC）。APC与蛋白S复合并通过因子Va和VIIIa的失活来调节凝血酶的产生。在缺乏状态下，PC作为凝血过程的关键调节剂的作用凸显。其中PC的杂合性缺乏会增加静脉血栓栓塞（VTE）的风险，当处于纯合缺陷状态时，胎儿可能发生致命性并发症,包括暴发性紫癜和弥散性血管内凝血(DIC).在VTE的研究中，蛋白C通常与其他因素如蛋白S和抗凝血酶一起测量作为筛选。显色PC测定，本章中描述的协议，使用PC的活化剂定量血浆中功能性PC的量,其中颜色变化程度与样品中存在的PC的量成比例。其他方法,包括基于功能凝血的检测和抗原检测，可用；然而，本章将不提供这些测定的方案。
