Physiological mechanisms for metalloproteinase activation

Matrix Suppl. 1992;1:224-30.


The activation of procollagenase and prostromelysin by mechanisms that might be functional in vivo has been investigated. Studies with cell monolayers plated onto collagen films have indicated key roles for plasmin and TIMP in these processes. Prostromelysin activation could be rapidly effected by fibroblast monolayers in the presence of plasminogen, with identical kinetics to plasminogen-streptokinase generated plasmin. Procollagenase activation by plasmin was shown to be poor, although an M(r) shift of 11,000 occurred. Activation was enhanced ten-fold by the presence of active stromelysin even at a very low molar ratio. A tumour cell line secreting procollagenase but not stromelysin was found to be dependent upon the addition of both stromelysin and plasminogen to effect degradation of collagen films. Biochemical studies of metalloproteinase activation were carried out using other purified proteinases synthesized by connective tissue cells including endopeptidase 24.11, endopeptidase-2, cathepsin B and cathepsin L. None was a particularly effective activator relative to plasmin, but cathepsin B was shown to activate stromelysin. By use of both cell model systems and biochemical studies of purified enzymes we have found that the role of plasmin as the major metalloproteinase activator in normal connective tissue cells remains unchallenged.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Endopeptidases / pharmacology*
  • Enzyme Activation / drug effects
  • Enzyme Precursors / drug effects*
  • Enzyme Precursors / metabolism
  • Extracellular Matrix Proteins / drug effects
  • Extracellular Matrix Proteins / metabolism
  • Fibrinolysin* / pharmacology
  • Glycoproteins / pharmacology
  • Humans
  • Metalloendopeptidases / drug effects
  • Metalloendopeptidases / metabolism*
  • Molecular Sequence Data
  • Neoplasm Proteins / drug effects
  • Neoplasm Proteins / metabolism
  • Plasminogen / pharmacology
  • Recombinant Proteins / drug effects
  • Recombinant Proteins / metabolism
  • Tissue Inhibitor of Metalloproteinases
  • Tumor Cells, Cultured
  • Urinary Bladder Neoplasms / pathology


  • Enzyme Precursors
  • Extracellular Matrix Proteins
  • Glycoproteins
  • Neoplasm Proteins
  • Recombinant Proteins
  • Tissue Inhibitor of Metalloproteinases
  • Plasminogen
  • Endopeptidases
  • Fibrinolysin
  • Metalloendopeptidases
  • prostromelysin