title: The interaction of alpha2-macroglobulin with proteinases. Binding and inhibition of mammalian collagenases and other metal proteinases.
abstract: 1. Experiments were performed to determine whether the specific collagenases and other metal proteinases are bound and inhibited by alpha(2)-macroglobulin, as are endopeptidases of other classes. 2. A specific collagenase from rabbit synovial cells was inhibited by human serum. The inhibition could be attributed entirely to alpha(2)-macroglobulin; alpha(1)-trypsin inhibitor was not inhibitory. alpha(2)-Macroglobulin presaturated with trypsin or cathepsin B1 did not inhibit collagenase, and pretreatment of alpha(2)-macroglobulin with collagenase prevented subsequent reaction with trypsin. The binding of collagenase by alpha(2)-macroglobulin was not reversible in gel chromatography. 3. The collagenolytic activity of several rheumatoid synovial fluids was completely inhibited by incubation of the fluids with alpha(2)-macroglobulin. 4. The collagenase of human polymorphonuclear-leucocyte granules showed time-dependent inhibition by alpha(2)-macroglobulin. 5. The collagenolytic metal proteinase of Crotalus atrox venom was inhibited by alpha(2)-macroglobulin. 6. The collagenase of Clostridium histolyticum was bound by alpha(2)-macroglobulin, and inhibited more strongly with respect to collagen than with respect to a peptide substrate. 7. Thermolysin, the metal proteinase of Bacillus thermoproteolyticus, was bound and inhibited by alpha(2)-macroglobulin. 8. It was shown by polyacrylamidegel electrophoresis of reduced alpha(2)-macroglobulin in the presence of sodium dodecyl sulphate that synovial-cell collagenase, clostridial collagenase and thermolysin cleave the quarter subunit of alpha(2)-macroglobulin near its mid-point, as do serine proteinases. 9. The results are discussed in relation to previous work, and it is concluded that the characteristics of interaction of the metal proteinases with alpha(2)-macroglobulin are the same as those of other proteinases.
mesh_terms: D000818:Animals; D002250:Carbon Radioisotopes; D002850:Chromatography, Gel; D004589:Electrophoresis, Disc; D005347:Fibroblasts / Q000201:enzymology; D006801:Humans; D005779:Immunodiffusion; D007122:Immunoelectrophoresis; D007962:Leukocytes / Q000201:enzymology; D008259:Macroglobulins / Q000378:metabolism*; D008667:Metalloproteins; D003012:Microbial Collagenase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism*; D011480:Protease Inhibitors; D011485:Protein Binding; D011817:Rabbits; D012910:Snake Venoms; D012967:Sodium Dodecyl Sulfate; D013582:Synovial Fluid / Q000201:enzymology; D013820:Thermolysin / Q000037:antagonists & inhibitors; D014357:Trypsin
chemical_list: D002250:Carbon Radioisotopes; D008259:Macroglobulins; D008667:Metalloproteins; D011480:Protease Inhibitors; D012910:Snake Venoms; D012967:Sodium Dodecyl Sulfate; D010447:Peptide Hydrolases; D014357:Trypsin; D013820:Thermolysin; D003012:Microbial Collagenase