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Autolysis studies of cathepsin D
Hoppe-Seyler'S Zeitschrift Fur Physiologische Chemie
|March 1, 1982
Summary
Bovine spleen cathepsin D undergoes autolytic degradation at pH 3.5, fragmenting into smaller pieces. Enzyme inactivation rates increase as cathepsin D concentration decreases during this process.
Area of Science:
- Biochemistry
- Enzymology
- Protein Chemistry
Background:
- Cathepsin D is a key aspartic protease involved in protein degradation.
- Understanding its autolytic properties is crucial for its biological function and potential therapeutic applications.
Purpose of the Study:
- To investigate the autolytic degradation of bovine spleen cathepsin D at acidic pH.
- To characterize the fragmentation pattern and conformational changes during autolysis.
- To determine the kinetics of enzyme inactivation.
Main Methods:
- Incubation of cathepsin D at pH 3.5.
- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).
- Gel filtration chromatography.
- Circular dichroism spectroscopy.
- Enzyme activity assays.
Main Results:
- Autolysis at pH 3.5 led to fragmentation of cathepsin D, initially forming Mr 30,000 and 15,000 fragments, followed by smaller peptides.
- Near-ultraviolet circular dichroism revealed conformational changes during autolysis.
- Enzyme inactivation followed biphasic first-order kinetics, with rates increasing at lower enzyme concentrations.
Conclusions:
- Cathepsin D undergoes autolytic degradation at acidic pH, altering its structure and activity.
- The observed fragmentation and inactivation kinetics provide insights into the enzyme's stability and degradation pathways.