Porter W R, Staack H, Brandt K, Manning M C
Department 493, Abbott Laboratories, Abbott Park, IL 60064.
Thromb Res. 1993 Aug 15;71(4):265-79. doi: 10.1016/0049-3848(93)90196-u.
Exposure of low molecular weight urokinase (LMW-UK) to prolonged heating (60 degrees C, 10 hours) is used to inactivate possible viral contaminants. This process leads to a significant loss of active enzyme. Amidolytic activity was monitored following heat treatment in order to establish the conditions for maintaining the optimal stability of LMW-UK. The effects of pH, ionic strength, protein concentration, and various ionic additives were examined. While LMW-UK is stable across a wide pH range (pH 2-11), heating LMW-UK in aqueous solution leads to complete loss of activity except between pH 4 and 7.5. The mechanism of inactivation was delineated using activity assays as well as turbimetric and spectroscopic methods. Thermal inactivation occurs via aggregation of unfolded LMW-UK, followed by subsequent precipitation. Threshold effects upon the thermally-induced aggregation of LMW-UK were observed.
低分子量尿激酶（LMW-UK）经长时间加热（60摄氏度，10小时）处理以灭活可能存在的病毒污染物。此过程会导致活性酶大量损失。热处理后监测酰胺水解活性，以确定维持LMW-UK最佳稳定性的条件。研究了pH值、离子强度、蛋白质浓度和各种离子添加剂的影响。虽然LMW-UK在较宽的pH范围内（pH 2-11）稳定，但在水溶液中加热LMW-UK会导致活性完全丧失，pH 4至7.5之间除外。使用活性测定以及比浊法和光谱法来描述失活机制。热失活通过未折叠的LMW-UK聚集，随后沉淀而发生。观察到了对LMW-UK热诱导聚集的阈值效应。
