Rick M E, Popovsky M A, Krizek D M
Br J Haematol. 1985 Nov;61(3):477-86. doi: 10.1111/j.1365-2141.1985.tb02851.x.
The factors responsible for the lability of factor VIII coagulant activity (VIII:C) and factor VIII coagulant antigen (VIII:CAg) are poorly understood. In this study the VIII:C and VIII:CAg are studied after incubation with plasmin, trypsin or alpha-chymotrypsin. Both isolated human VIII:CAg and VIII:CAg associated with factor VIII-related antigen (VIII R:Ag) are evaluated. The antigenic sites of the VIII:CAg are somewhat more stable to the action of these enzymes than the functional activity, although both follow a generally parallel degradation. A biphasic decay curve is seen in the initial time points. No stabilization of the functional or antigenic reactivity is observed in the presence of the VIII R:Ag. Lower concentrations of each enzyme cause an initial rise in the factor VIII:C in the presence of VIII R:Ag, but not in the isolated VIII:CAg. Higher concentrations of alpha-chymotrypsin cause activation of VIII:C and a slight decrease in the VIII:CAg values in both preparations. These enzymes may play a modulating role in the coagulation cascade through the activation and degradation of VIII:C and VIII:CAg.
导致凝血因子VIII促凝活性（VIII:C）和凝血因子VIII促凝抗原（VIII:CAg）不稳定的因素目前还知之甚少。在本研究中，在与纤溶酶、胰蛋白酶或α-糜蛋白酶孵育后，对VIII:C和VIII:CAg进行了研究。对分离的人VIII:CAg和与因子VIII相关抗原（VIII R:Ag）相关的VIII:CAg均进行了评估。VIII:CAg的抗原位点对这些酶作用的稳定性略高于功能活性，尽管二者的降解过程总体上是平行的。在最初的时间点观察到双相衰变曲线。在VIII R:Ag存在的情况下，未观察到功能或抗原反应性的稳定。在VIII R:Ag存在时，较低浓度的每种酶会导致因子VIII:C最初升高，但在分离的VIII:CAg中则不会。较高浓度的α-糜蛋白酶会导致两种制剂中的VIII:C激活以及VIII:CAg值略有下降。这些酶可能通过激活和降解VIII:C和VIII:CAg在凝血级联反应中发挥调节作用。
