An Enzyme with Collagenolytic Activity from Dog Pancreatic Juice

Abstract

AbstractA purified collagenase has been isolated from the pancreatic juice of dogs prepared with pancreatic fistulae and stimulated to secrete the enzyme by injection of high quality pancreozymin. The purification steps included the use of affinity chromatography employing a Sepharose‐collagen column. The isolated enzyme had relatively high specific activity, was able to digest extracted, undenatured collagen to peptides of relatively small size, and could act on so‐called insoluble beef tendon collagen. Unlike clostridial collagenases, and most tissue collagenases, but resembling the collagenase of the hepatopancreases of crab and crayfish, the canine pancreatic collagenase was inhibited by diisopropylphosphorofluoridate, albeit in relatively high concentrations. Resembling the bacterial collagenase and tissue collagenases, but differing from the collagenase of crab hepatopancreas, the canine pancreatic collagenase was inhibited by cysteine. Resembling other pancreatic proteases, the pancreatic collagenase was inhibited by glycoproteins, human serum, or to a small extent by soy bean trypsin inhibitor. Apparently, just as carnivorous mammals have evolved with a specific elastase homologous with trypsin and chymotrypsin, they also have evolved in some instances with a specific collagenase; its homology with the other serine proteases is not yet established, although it appears to have properties intermediate between those of a serine protease and those of most tissue collagenases. The latter group of enzymes have been considered to be metallo‐enzymes. One may speculate that non‐carnivores would not have had selective pressure to evolve with a digestive collagenase, and that even the selective pressure to develop with a digestive collagenase in non‐carnivores would not be so great since the other serine proteases can digest denatured collagen. Finally, a new radioactive method of assay for collagenases is described.