Mielicki W P, Gordon S G
University of Colorado Health Science Center, Denver 80262.
Blood Coagul Fibrinolysis. 1993 Jun;4(3):441-6. doi: 10.1097/00001721-199306000-00008.
The cysteine proteinase, cancer procoagulant (CP; EC 3.4.22.26) was isolated from human amnion-chorion and purified by precipitation with polyethylene glycol and either ion exchange or immunoaffinity chromatography. A new, sensitive, three-stage chromogenic assay was developed for determination of CP factor X-activating activity. Using this assay some properties including dose-response, effect of calcium, phospholipid and pH on the activation of factor X by CP was determined. There was an excellent linear correlation (r2 = 0.99) between concentration and the enzymatic activity of CP. The activation of factor X by purified CP was calcium dependent with an optimum calcium concentration of 7 mM. CP was not phospholipid dependent. There was a rather broad pH optimum between pH 6.9 and 7.25 for the activation of factor X by CP.
半胱氨酸蛋白酶——癌促凝素（CP；EC 3.4.22.26）从人羊膜 - 绒毛膜中分离出来，并通过聚乙二醇沉淀以及离子交换或免疫亲和层析进行纯化。开发了一种新的、灵敏的三阶段显色测定法来测定CP激活因子X的活性。使用该测定法确定了包括剂量反应、钙、磷脂和pH对CP激活因子X的影响等一些特性。CP的浓度与酶活性之间存在极好的线性相关性（r2 = 0.99）。纯化的CP对因子X的激活依赖于钙，最佳钙浓度为7 mM。CP不依赖磷脂。CP激活因子X的最适pH在6.9至7.25之间，范围相当宽。
