Studies on the Interaction between Leukocyte Elastase, Antileukoproteinase and the Plasma Proteinase Inhibitors α1-Proteinase Inhibitor and α2-Macroglobulin

Abstract

The dominating inhibitor of leukocyte elastase in human respiratory tract secretions is a low molecular mass inhibitor, designated anti-leukoproteinase. An equimolar antileukoproteinase-elastase complex was produced and subjected to gel filtration after differing time intervals and was found to be stable. On addition to human serum, however, elastase dissociated from antileukoproteinase and formed a complex with .alpha.1-proteinase inhibitor. A small amount of elastase was also found bound to .alpha.2-macroglobulin. Antileukoproteinase was capable of inhibiting elastase bound to .alpha.2-macroglobulin. This inhibition was more complete and more rapid when the .alpha.2-macroglobulin-elastase complex was in a molar ratio of 1:1 than in a ratio of 1:2.