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Human low-molecular-weight urinary urokinase. Partial characterization and preliminary sequence data of the two
European Journal of Biochemistry
|July 1, 1982
Summary
Low-molecular-weight urokinase, a key enzyme in clot breakdown, was analyzed and found to consist of distinct subforms. These subforms share similar properties, suggesting a common precursor structure.
Area of Science:
- Biochemistry
- Molecular Biology
- Proteolysis
Background:
- Urokinase is a serine protease crucial for fibrinolysis.
- Understanding urokinase's structure is vital for developing thrombolytic therapies.
Purpose of the Study:
- To characterize the subforms of low-molecular-weight urokinase.
- To elucidate the structural basis of urokinase's enzymatic activity.
Main Methods:
- Isoelectric focusing (analytical and preparative) was used to separate urokinase subforms.
- Amino acid sequencing and homology analysis were performed on the separated chains.
Main Results:
- Five major subforms of low-molecular-weight urokinase were identified with similar molecular weights and activities.
- The enzyme comprises two polypeptide chains linked by a disulfide bridge.
- Sequence analysis revealed homology to other serine proteases and plasmin.
Conclusions:
- Low-molecular-weight urokinase likely originates from a single-chain precursor.
- Structural similarities suggest a conserved activation mechanism for serine proteases.