Cationic proteins of human granulocytes. V. Interaction with plasma protease inhibitors.
Several cationic proteins of human granulocytes possess chymotrypsin-like and bactericidal activities. The heat-labile chymotrypsin-like activity is inhibited by serum, owing to complex formation with alpha2-macroglobulin and alpha1-antitrypsin. The molar affinity of the cationic proteins for alpha2-macroglobulin is much higher than that for alpha1-antitrypsin. The results indicate that the molar combining ratios are 1:1 for cationic protein to alpha1-antitrypsin and 2:1 for cationic protein to alpha2-macroglobulin. The proteolytic activity against fibrinogen and casein is inhibited by both alpha2-macroglobulin and alpha1-antitrypsin, whereas the activity against small molecular synthetic substrates is inhibited by alpha1-antitrypsin but not alpha2-macroglobulin. The heat-stable bactericidal action of the cationic proteins against Staphylococcus was also inhibited by serum, probably owing to complex formation with alpha2-macroglobulin and alpha1-antitrypsin.
D001798:Blood Proteins / Q000378:metabolism* / Q000494:pharmacology; D004950:Esterases / Q000037:antagonists & inhibitors; D006098:Granulocytes / Q000378:metabolism*; D006801:Humans; D007962:Leukocytes / Q000378:metabolism*; D011480:Protease Inhibitors; D013210:Staphylococcus / Q000187:drug effects; D000515:alpha 1-Antitrypsin / Q000494:pharmacology; D000511:alpha-Macroglobulins / Q000494:pharmacology
D001798:Blood Proteins; D011480:Protease Inhibitors; D000515:alpha 1-Antitrypsin; D000511:alpha-Macroglobulins; D004950:Esterases