Interaction between human pancreatic elastase and plasma protease inhibitors.
1 ml of human serum inhibits about 0.9 mg of purified human pancreatic elastase owing to complexation with alpha 1-antitrypsin and alpha 2-macroglobulin. On addition to serum, elastase is preferentially bound by alpha 2-macroglobulin. The complexes between elastase and alpha 1-antitrypsin and alpha 2-macroglobulin, respectively, migrate as alpha 2-globulin on agarose gel electrophoresis. Elastase bound by alpha 1-antitrypsin is precipitated by antibodies against enzyme as well as inhibitor, while the alpha 2-macroglobulin-bound elastase is only precipitated by antibodies against the inhibitor. The molar combining ratio for elastase/alpha 1-antitrypsin is 1:1 and for elastase/alpha 2-macroglobulin 2:1. The elastase bound by alpha 2-macroglobulin retains its activity against low molecular weight substrates, while that bound by alpha 1-antitrypsin is enzymologically inactive.
D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D007700:Kinetics; D010179:Pancreas / Q000201:enzymology*; D010196:Pancreatic Elastase / Q000378:metabolism*; D011485:Protein Binding; D000515:alpha 1-Antitrypsin / Q000494:pharmacology; D000511:alpha-Macroglobulins / Q000494:pharmacology
D000515:alpha 1-Antitrypsin; D000511:alpha-Macroglobulins; D010196:Pancreatic Elastase