Johansen H T, Briseid K
Acta Pharmacol Toxicol (Copenh). 1984 Jul;55(1):25-32. doi: 10.1111/j.1600-0773.1984.tb01958.x.
Most reports in the literature state that human plasma kallikrein does not destroy the capacity of human high molecular weight kininogen (HMrK) to function as a cofactor in the contact phase activation of factor XII. In the present work preparations of highly purified human plasma kallikrein that showed high plasminogen activator (PGA) activities rapidly reduced the cofactor function of human HMrK. Gel electrophoresis with SDS without reduction showed that all kallikrein preparations tested contained two protein bands, one major band with a Mr of about 83,000, and one weak band with a Mr of 80,000. The main band is probably identical with kallikrein I, which Levison & Tomalin (1982b), using Ac-Pro-Phe-Arg-OMe-HCl as substrate, found to be ten times more active (in terms of kcat/Km) than kallikrein II with Mr 3000 daltons lower. The rate of HMrK destruction in our experiments varied with the kallikrein preparation used, but assays of their hydrolytic activities against benzoyl arginine ethylester (BAEe) or the plasma kallikrein selective tripeptide substrate H-D-Pro-Phe-Arg-pNA (S-2302) did not discriminate between enzyme preparations with different HMrK-destroying capacities. Assay of PGA activities demonstrated a correlation between the level of PGA measured, and the HMrK-destroying capacity.
文献中的大多数报道称，人血浆激肽释放酶不会破坏人高分子量激肽原（HMrK）作为因子XII接触相激活辅因子的功能。在本研究中，显示出高纤溶酶原激活剂（PGA）活性的高纯度人血浆激肽释放酶制剂迅速降低了人HMrK的辅因子功能。未还原的SDS凝胶电泳表明，所有测试的激肽释放酶制剂均含有两条蛋白带，一条主要带的Mr约为83,000，一条弱带的Mr为80,000。主要带可能与激肽释放酶I相同，Levison和Tomalin（1982b）使用Ac-Pro-Phe-Arg-OMe-HCl作为底物，发现其活性（以kcat/Km计）比Mr低3000道尔顿的激肽释放酶II高十倍。在我们的实验中，HMrK的破坏速率随所用激肽释放酶制剂的不同而变化，但对其针对苯甲酰精氨酸乙酯（BAEe）或血浆激肽释放酶选择性三肽底物H-D-Pro-Phe-Arg-pNA（S-2302）的水解活性测定并不能区分具有不同HMrK破坏能力的酶制剂。PGA活性测定表明，所测PGA水平与HMrK破坏能力之间存在相关性。
