Plasminogen activation by pro-urokinase in complex with its receptor: Dependence on a tripeptide (Spectrozyme plasmin)

Jieyi Wang*, Andrew Mazar, Nancy Quan, Andrew Schneider, Jack Henkin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


The intrinsic activity of single-chain pro-urinary-type plasminogen activator (pro-uPA) and whether its receptor (uPAR) potentiates this activity remains controversial. In this report, the pro-uPA/uPAR-(1281)-peptide complex in solution is shown to have equivalent plasminogen-activator activity to that of active two-chain uPA (tc-uPA). However, the activity of the complex was dependent on a synthetic tripeptide. Spectrozyme plasmin (Spl,H-D-2-aminohexanoic acid(Ahx)-hexatyrosyl-lysine-p-nitroanilide), which can also be used as a chromogenic substrate for plasmin. Furthermore, this activity could be completely suppressed by commonly used carrier proteins and detergents. The pro-uPA/uPAR-(1-281)-peptide complex at 1 nM displayed similar activity to that of tc-uPA for either [Glul]plasminogen or [Lys77]plasminogen in chromogenic assays with Spl present as the plasmin substrate. When assayed with another plasmin substrate. S2251, the pro- uPA/uPAR-(1-281)-peptide complex was unable to activate plasminogen. The pro- uPA/uPAR-(1-281)-peptide complex and tc-uPA also showed a similar extent of plasminogen activation as measured by SDS/PAGE, when incubated with plasminogen and Spl in the presence of 100 μM aprotinin, and plasminogen activation by pro-uPA alone was also stimulated in the presence of Spl in this assay. Activation of plasminogen by the pro-uPA/uPAR-(1-281)-peptide strictly required the presence of Spl, and pro-uPA remained in single-chain form during these assays. This activity of the pro-uPA/uPAR-(1-281)-peptide complex but not that of tc-uPA was completely inhibited by human serum albumin, bovine serum albumin, Tween-80, Triton X-100, and Pluronic-F68. Taken together, the data indicates that uPAR-(1-281)-peptide itself is not sufficient to augment pro-uPA activity and the presence of an effector molecule (e.g. Spl) is required to elicit the full plasminogen-activator activity of the pro-uPA/uPAR (1-281)-peptide complex. It remains to be seen whether there is a physiological counterpart to this phenomenon.

Original languageEnglish (US)
Pages (from-to)256-261
Number of pages6
JournalEuropean Journal of Biochemistry
Issue number1
StatePublished - 1997


  • Extracellular proteolysis
  • Plasminogen
  • Urokinase
  • Urokinase receptor
  • Zymogen activation

ASJC Scopus subject areas

  • Biochemistry


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