Related Experiment Videos
Pressure effects on proteolysis catalysed by calpain
P Bessiere1, F Bancel, P Cottin
1Laboratoire de Biochimie et Technologie des Aliments, UA-429 INRA, Institut des Sciences et Techniques des Aliments de Bordeaux, Université Bordeaux I, Talence, France.
Biochemistry and Molecular Biology International
|March 27, 1999
Summary
High pressure significantly impacts mu- and m-calpain activity and stability. Pressure inhibits autoproteolysis and affects enzyme-substrate binding, revealing insights into calpain
Area of Science:
- Biochemistry
- Enzymology
- Protein Science
Background:
- Calpains are neutral calcium-dependent heterodimeric proteinases.
- Understanding calpain regulation is crucial for cellular processes.
Purpose of the Study:
- To investigate the effects of hydrostatic pressure on mu- and m-calpain stability and specific activity.
- To elucidate the influence of pressure on calpain's catalytic mechanism and autoproteolysis.
Main Methods:
- Utilized a custom-built bioreactor for on-line spectrophotometric monitoring under pressure.
- Assessed proteinase activity and stability at varying hydrostatic pressures up to 1500 bar.
Main Results:
- Both mu- and m-calpain exhibited baro-sensitivity, with half-lives of 6 and 11 minutes at 1500 bar, respectively.
- Enzyme activity showed biphasic behavior, with initial activation followed by inhibition at higher pressures.
- Pressure inhibited calpain autoproteolysis and altered the balance between catalytic and substrate-binding steps.
Conclusions:
- Hydrostatic pressure significantly modulates calpain function, affecting both stability and catalytic activity.
- Pressure-induced changes in Ca2(+) binding may contribute to the inhibition of proteolytic activity.
- These findings provide insights into the catalytic mechanism of calpains under varying pressure conditions.