Regulation of fibrinolytic activity of neutrophil leukocyte elastase, plasmin, and miniplasmin by plasma protease inhibitors.
The effect of solid-phase fibrin on the inactivation of plasmin, miniplasmin, and neutrophil leukocyte elastase (PMN-elastase) by plasma protease inhibitors (alpha 2-antiplasmin, alpha 1-protease inhibitor, alpha 2-macroglobulin) was studied. In Hanks' balanced salt solution, fibrin reduces the second-order rate constant for the inhibition of PMN-elastase by alpha 1-protease inhibitor from 8,760 x 10(4) to 4 x 10(4) M-1.s-1 and by alpha 2-macroglobulin from 121 x 10(4) to 1.8 x 10(4) M-1.s-1. The rate constant for miniplasmin inactivation by alpha 2-antiplasmin decreases from 99 x 10(4) to 1 x 10(4) M-1.s-1, by alpha 2-macroglobulin from 78 x 10(4) to 1.8 x 10(4) M-1.s-1, and by alpha 1-protease inhibitor from 0.11 x 10(4) M-1.s-1 to 0. Plasmin bound to fibrin is completely protected against alpha 2-macroglobulin and alpha 1-protease inhibitor, whereas the rate constant for the inactivation by its primary plasma inhibitor alpha 2-antiplasmin is reduced from 430 x 10(4) to 1.08 x 10(4) M-1.s-1. The competition of substrate and inhibitor for the enzyme was also studied, using fibrin preincubated with inhibitor. Under our pseudo-first-order experimental conditions, fibrin completely eliminates those interactions, the second-order rate constant of which is 1.1 x 10(5) M-1.s-1 or less in a system without fibrin surface.
Kolev
K
K
Department of Biochemistry II, Semmelweis University of Medicine, Budapest, Hungary.
Léránt
I
I
Tenekejiev
K
K
Machovich
R
R
D001667:Binding, Competitive; D005337:Fibrin / Q000378:metabolism; D005341:Fibrinolysin / Q000037:antagonists & inhibitors*; D005342:Fibrinolysis / Q000187:drug effects*; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D019272:Leukocyte Elastase; D009504:Neutrophils / Q000201:enzymology*; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors*; D010446:Peptide Fragments / Q000037:antagonists & inhibitors*; D000515:alpha 1-Antitrypsin / Q000494:pharmacology; D000979:alpha-2-Antiplasmin / Q000494:pharmacology; D000511:alpha-Macroglobulins / Q000494:pharmacology
D010446:Peptide Fragments; D000515:alpha 1-Antitrypsin; D000979:alpha-2-Antiplasmin; D000511:alpha-Macroglobulins; C019493:miniplasmin; D005337:Fibrin; D010196:Pancreatic Elastase; D019272:Leukocyte Elastase; D005341:Fibrinolysin