Heparin strongly decreases the rate of inhibition of neutrophil elastase by alpha 1-proteinase inhibitor.

摘要: Heparin depresses the second-order rate constant ka for inhibition of neutrophil elastase by alpha 1-proteinase inhibitor. High molecular mass heparin decreases from 1.3 x 10(7) M-1 s-1 to a limit 4.6 10(4) s-1. Low is about 7-fold less effective. Dermatan sulfate and chondroitin are efficient. preparations used in clinical care also strongly depress when tested at concentrations corresponding their efficacy. elastase/eglin c cathepsin G/alpha inhibitor systems but not that inhibitor/pancreatic or trypsin pairs. These results, together with Sepharose-heparin binding studies, indicate ka-depressing effect polymer related its ability form tight complex One mol high binds 3 Kd 3.3 nM. 1:1 stoichiometry 89 For both heparins lowest fully saturated heparin. From this we conclude ka, because heparin-elastase able slowly react dissociates complex. findings may have important pathophysiological bearing.