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Structural relationship between human high and low molecular mass urokinase
Hoppe-Seyler'S Zeitschrift Fur Physiologische Chemie
|February 1, 1982
Summary
Human urokinase, a key enzyme, exists in low and high molecular forms. The low molecular form arises from proteolytic degradation of the high molecular form, specifically targeting a 20,000 Da chain.
Area of Science:
- Biochemistry
- Molecular Biology
- Enzymology
Background:
- Human urokinase is a serine protease involved in fibrinolysis.
- It exists in different molecular forms, with implications for its biological activity.
- Understanding the structural differences between these forms is crucial for elucidating their functions.
Purpose of the Study:
- To elucidate the structural composition of human low molecular mass urokinase.
- To determine the relationship between high and low molecular mass urokinase forms.
- To identify the specific molecular changes during the transformation process.
Main Methods:
- Reductive cleavage of disulfide bonds.
- Gel filtration chromatography for peptide chain isolation.
- Amino acid sequencing and composition analysis.
Main Results:
- Human low molecular mass urokinase comprises two polypeptide chains (30,000 Da and 2,427 Da).
- The 2,427 Da chain contains hexosamines and has a determined amino acid sequence.
- The 30,000 Da chains are identical in both low and high molecular mass urokinase; the 2,427 Da chain differs from the high molecular form's 20,000 Da chain.
Conclusions:
- The transformation from high to low molecular mass urokinase is due to limited proteolytic degradation of the 20,000 Da chain.
- This proteolytic event specifically generates the distinct 2,427 Da chain found in the low molecular form.
- Structural analysis provides key insights into urokinase isoform generation and function.