The role of alpha1-antitrypsin and alpha-macroglobulins in the uptake of proteinase by rabbit alveolar macrophages.
Proteinases in plasma bind largely to alpha1-antitrypsin and alpha-macroglobin. The latter is represented in humans by alpha2-macroglobulin and in the rabbit by alpha2-macroglobulin and alpha1-macroglobulin. There is a selective and rapid uptake of proteinase-macroglobulin complexes by rabbit alveolar macrophages. It was found that complexes of labelled trypsin or subtilopeptidase A with rabbit alpha1-antitrypsin do not become similarly associated with rabbit alveolar macrophages. Moreover, proteinase-alpha1-antitrypsin complexes failed to inhibit the uptake of labelled proteinase-macroglobulin complexes. Thus, the interaction with macrophages of proteinase-macroglobulin complexes represents a pathway of proteinase metabolism distinct from that involving proteinase bound to alpha1-antitrypsin.
D000818:Animals; D066298:In Vitro Techniques; D008264:Macrophages / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism*; D011817:Rabbits; D014357:Trypsin / Q000378:metabolism; D000515:alpha 1-Antitrypsin / Q000378:metabolism / Q000494:pharmacology*; D000511:alpha-Macroglobulins / Q000378:metabolism / Q000494:pharmacology*
D000515:alpha 1-Antitrypsin; D000511:alpha-Macroglobulins; D010447:Peptide Hydrolases; D014357:Trypsin