title: Neutrophil proteases in plasminogen activation.
abstract: Leukocyte elastase and leukocyte cathepsin G degrade porcine plasminogen primarily by hydrolysis of the A447-I448 bond between kringle4 and kringle5. The rate of formation of des-kringle1-4-plasminogen is faster with elastase (k"obs greater than 10(5) mol-1 s-1) than with cathepsin G (kobs less than 300 mol-1 s-1). In contrast to elastase, leukocyte cathepsin G does not inactivate alpha 2-antiplasmin. Consequently, plasminogen activation by urokinase in the presence of alpha 2-antiplasmin is elastase-dependent, but cathepsin G does not overcome the action of alpha 2-antiplasmin. The rate-enhancing effect of fibrin(ogen) fragments in plasminogen activation by tissue-type plasminogen activator is also disabled efficiently by these proteases. It is concluded that enhancement of plasmin expression by neutrophil proteases is accounted for primarily by the action of elastase.
authors.affiliation: Section of Hematology Research, Mayo Clinic and Foundation, Rochester, MN 55905.
authors.forename: R
authors.initials: R
authors.lastname: Machovich
authors.forename: A
authors.initials: A
authors.lastname: Himer
authors.forename: W G
authors.initials: WG
authors.lastname: Owen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D056649:Cathepsin G; D002403:Cathepsins / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism*; D005341:Fibrinolysin / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D019272:Leukocyte Elastase; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000201:enzymology*; D010196:Pancreatic Elastase / Q000378:metabolism; D010958:Plasminogen / Q000378:metabolism*; D012697:Serine Endopeptidases; D013552:Swine; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism; D000511:alpha-Macroglobulins / Q000378:metabolism
chemical_list: D000511:alpha-Macroglobulins; C024668:plasmin-alpha(2)-macroglobulin complex; D010958:Plasminogen; D002403:Cathepsins; D010450:Endopeptidases; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D010196:Pancreatic Elastase; D019272:Leukocyte Elastase; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator