title: Procollagen processing. Limited proteolysis of COOH-terminal extension peptides by a cathepsin-like protease secreted by tendon fibroblasts.
abstract: An enzymatic activity, capable of removing the COOH-terminal extensions of type I chick procollagen, has been demonstrated in embryonic chick tendons and in cultured tendon fibroblasts utilizing two new methods of analysis. The protease was purified by a combination of ultrafiltration concanavalin A affinity chromatography and gel filtration. The isolated protein has an apparent Mr of 43,000 by gel filtration and sodium dodecyl sulfate gel electrophoresis. The enzyme shows a major pH optimum at 4.2 and is susceptible to inhibitors such as pepstatin and leupeptin; it therefore seems related to the cathepsins. The possibility that this enzyme plays a role in the limited proteolytic processing of procollagen is discussed.
mesh_terms: D000818:Animals; D002403:Cathepsins; D002478:Cells, Cultured; D002642:Chick Embryo; D005347:Fibroblasts / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D011347:Procollagen / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology; D013710:Tendons / Q000378:metabolism*
chemical_list: D011347:Procollagen; D011480:Protease Inhibitors; D002403:Cathepsins; D010447:Peptide Hydrolases