Kajihara J, Shibata K, Nakano Y, Nishimuro S, Kato K
JCR Pharmaceuticals Co., Ltd., Kobe, Japan.
Biochim Biophys Acta. 1994 Mar 2;1199(2):202-8. doi: 10.1016/0304-4165(94)90116-3.
Human urokinase (UK) was conjugated with polyethylene glycol-polypropylene glycol (PEG-PPG) and its physicochemical properties were examined. PEG-PPG modification decreased the activity for plasminogen activation, but increased the half-life of this protein when injected intravenously in rabbits. Kinetic analysis of PEG-PPG conjugated UK (PEG-PPG-UK) revealed that the kcat for plasminogen activation decreased 1/5-fold with the increase of Km in comparison with that of UK, although these parameters for cleavage of synthetic substrate (S-2444) did not change. However, the inhibitor constant of PEG-PPG-UK for plasminogen activator inhibitor 1 (PAI 1) was equal to that of UK. Peptide mapping analysis revealed that PEG-PPG binding sites were mainly determined to be Lys 35, 46, 61, 98, 120 and 135 in A-chain and Lys 211, 300, 318, 338, 348, 383 and 404 in B-chain. In addition, the modification rates of A and B-chain were 37.8% and 19.8% on average, respectively.
将人尿激酶（UK）与聚乙二醇 - 聚丙二醇（PEG - PPG）偶联，并检测其理化性质。PEG - PPG修饰降低了纤溶酶原激活活性，但在兔静脉注射时延长了该蛋白的半衰期。对PEG - PPG偶联的UK（PEG - PPG - UK）的动力学分析表明，与UK相比，随着Km增加，纤溶酶原激活的kcat降低了1/5倍，尽管其对合成底物（S - 2444）的切割参数没有变化。然而，PEG - PPG - UK对纤溶酶原激活物抑制剂1（PAI 1）的抑制常数与UK相等。肽图分析表明，PEG - PPG结合位点主要确定为A链中的Lys 35、46、61、98、120和135以及B链中的Lys 211、300、318、338、348、383和404。此外，A链和B链的修饰率平均分别为37.8%和19.8%。
