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Substrate specificity of tissue-type and urokinase-type plasminogen activators
1Gaubius Institute TNO, Leiden, The Netherlands.
Biochemical and Biophysical Research Communications
|January 31, 1991
Summary
Tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA) both cleave arginyl bonds. However, t-PA shows a higher preference for arginyl bonds than u-PA, suggesting u-PA may cleave other bonds.
Area of Science:
- Biochemistry
- Proteolysis
- Enzymology
Background:
- Plasminogen activators, including tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA), are known to cleave specific bonds.
- Emerging evidence suggests these enzymes may also hydrolyze other proteins, such as fibronectin, beyond their primary substrates.
Purpose of the Study:
- To investigate the substrate specificity of t-PA and u-PA.
- To determine the preference of these plasminogen activators for arginyl versus lysyl peptide bonds.
Main Methods:
- Utilized tripeptidyl-p-nitroanilide substrates with either arginine or lysine at the P1 position.
- Quantified the arginine/lysine preference for both u-PA and t-PA.
Main Results:
- Both t-PA and u-PA demonstrated a preference for cleaving arginyl peptide bonds over lysyl peptide bonds.
- u-PA exhibited a significantly lower arginine/lysine preference (5.2–14.1) compared to t-PA (55.6–99.8).
Conclusions:
- t-PA and u-PA preferentially cleave arginyl bonds.
- The lower specificity of u-PA suggests it may have additional functions involving the cleavage of lysyl bonds, beyond plasminogen activation.