title: Abnormal breakdown of alpha2-macroglobulin-trypsin complex in cystic fibrosis.
abstract: The complex of trypsin with purified alpha2-macroglobulin from normals and patients with cystic fibrosis was studied. The formed complex failed to reveal any proteolytic activity toward a high molecular weight substrate whereas the esterolytic activity towards a low molecular weight substrate was retained. This esterolytic activity was resistant to inhibition by a high molecular weight inhibitor. During iincubation at 38 degrees C the complex with normal alpha2-macroglobulin was slowly inhibited by the high molecular weight inhibitor and regained activity with the high molecular weight substrate. This phenomenon was not obtained when the alpha2-macroglobulin from cystic fibrosis was examined. These data suggest that the gradual conversion of normal alpha2-macroglobulin-trypsin complex into an alpha2-macroglobulin fragment-trypsin complex is deficient in patients with cystic fibrosis.
mesh_terms: D003550:Cystic Fibrosis / Q000378:metabolism*; D006801:Humans; D011485:Protein Binding; D014357:Trypsin / Q000378:metabolism*; D014360:Trypsin Inhibitor, Kunitz Soybean / Q000494:pharmacology; D000511:alpha-Macroglobulins / Q000378:metabolism*
chemical_list: D000511:alpha-Macroglobulins; D014360:Trypsin Inhibitor, Kunitz Soybean; D014357:Trypsin