期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1981
卷号：78
期号：3
页码：1485-1489
DOI：10.1073/pnas.78.3.1485
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Preparations of outer membrane of two strains of Escherichia coli contain a protease that can activate the serum zymogen plasminogen to the active protease plasmin. The amount of plasmin formed is proportional to the membrane concentration. The kinetics of plasminogen activation are linear and obey the Michaelis--Menten rate equation. The Km(app) for the activation of dog plasminogen by E. coli outer membrane preparations is similar to the Km(app) for the activation of dog plasminogen by human urokinase. The E. coli enzyme is active in a membrane-associated form, as opposed to a secreted or soluble form, and is most likely a serine protease because it is inhibited by diisopropyl fluorophosphate. It is also inhibited from activating plasminogen by p-nitrophenyl-p-guanidinobenzoate and aprotinin. Analysis of the activation of plasminogen by the E. coli enzyme by NaDodSO4/polyacrylamide gel electrophoresis showed that the cleavage of plasminogen to plasmin was as specific as that exhibited in the activation of plasminogen to plasmin by urokinase. Possible in vivo roles for this plasminogen activator in E. coli outer membranes are discussed.
