Characterization of the activation of pro-urokinase by thermolysin

Patrick A. Marcotte*, Jack Henkin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


The bacterial metalloproteinase thermolysin catalyzes the efficient activation of pro-urokinase to an active high-molecular-weight form of the protein. Thermolysin and plasmin convert pro-urokinase to enzymes of essentially equal activities in amidolytic assays, but with different molecular structures. The B-chains of the proteins produced by thermolysin and plasmin are of the same size (33 kDa) and have the same amino-terminal sequences, demonstrating that the cleavage of the Lys158-Ile159 bond of pro-urokinase is catalyzed by both enzymes. However, thermolysin also reacts at additional sites in the growth factor domain of the A-chain at nearly the same rate as that of the activation reaction. Polypeptides derived from hydrolyses of the Glu3-Leu4, Tyr24-Phe25, Asn27-Ile28 and Lys36-Phe37 bonds are recovered after reduction of the activated protein. The carboxy-terminus of the A-chain has been shown to be Arg-156, a consequence of proteolysis of the Arg156-Phe157 bond. In contrast to plasmin, thermolysin activates thrombin-inactivated pro-urokinase nearly as rapidly as it does the native zymogen. Thermolysin provides a useful alternative to plasmin for the catalytic activation and analysis of pro-urokinase, since the bacterial metalloproteinase is stable in solution and not susceptible to inhibition by aprotinin and other serine proteinase inhibitors.

Original languageEnglish (US)
Pages (from-to)105-112
Number of pages8
JournalBiochimica et Biophysica Acta (BBA)/Protein Structure and Molecular
Issue number1
StatePublished - Jan 15 1993


  • Plasminogen activator
  • Pro-urokinase
  • Thermolysin
  • Urokinase

ASJC Scopus subject areas

  • Structural Biology
  • Biophysics
  • Biochemistry
  • Molecular Biology


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