title: Influence of elastin on the inhibition of leucocyte elastase by alpha 1-proteinase inhibitor and bronchial inhibitor. Potent inhibition of elastin-bound elastase by bronchial inhibitor.
abstract: We have investigated the effect of human lung elastin on the inhibition of human leucocyte elastase by human alpha 1-proteinase inhibitor and bronchial inhibitor. Elastin was unable to dissociate the elastase-inhibitor complexes during the 150 min of the elastolysis reaction. When elastase was added to mixtures of elastin and alpha 1-proteinase inhibitor, it was fully bound to the latter. The competition between elastin and bronchial inhibitor was also in favour of the latter, but a 1.5 molar excess of inhibitor over elastase was required to achieve total binding of the enzyme. About 25% of elastin-bound elastase was found to be resistant to the inhibitory effect of alpha 1-proteinase inhibitor. The major isoenzyme and the mixture of the three minor isoenzymes of elastase exhibited similar behaviour. By contrast, bronchial inhibitor was as efficient in inhibiting the elastin-bound elastase as it was in inhibiting the free enzyme. This inhibitor was also able to inhibit fully the fraction of elastin-bound elastase that was resistant to alpha 1-proteinase inhibitor. We also describe a rapid procedure for the isolation of gram quantities of alpha 1-proteinase inhibitor.
mesh_terms: D001798:Blood Proteins / Q000494:pharmacology*; D004549:Elastin / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D007962:Leukocytes / Q000201:enzymology*; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors*; D053491:Proteinase Inhibitory Proteins, Secretory; D011506:Proteins / Q000494:pharmacology*; D000515:alpha 1-Antitrypsin
chemical_list: D001798:Blood Proteins; D053491:Proteinase Inhibitory Proteins, Secretory; D011506:Proteins; D000515:alpha 1-Antitrypsin; D004549:Elastin; D010196:Pancreatic Elastase