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Phospholipase C from Bacillus cereus. Action on some artificial lecithins
Acta Chemica Scandinavica. Series B: Organic Chemistry and Biochemistry
|January 1, 1977
Summary
Phospholipase C from B. cereus efficiently hydrolyzes short-chain lecithins, with reaction rates increasing significantly above critical micelle concentrations. Enzyme activity is influenced by substrate chain length and deoxycholate presence.
Area of Science:
- Biochemistry
- Enzymology
- Molecular Biology
Background:
- Phospholipase C (PLC) is a key enzyme involved in phospholipid metabolism.
- Understanding PLC activity is crucial for various biological processes and biotechnological applications.
- The substrate specificity and kinetic behavior of PLC are influenced by substrate properties.
Purpose of the Study:
- To investigate the hydrolysis of various lecithins by phospholipase C from Bacillus cereus.
- To determine the effect of fatty acyl chain length on enzyme activity.
- To elucidate the kinetic properties, including Michaelis-Menten kinetics and the influence of critical micelle concentrations.
Main Methods:
- Enzyme kinetic assays were performed using different lengths of fatty acyl chain lecithins.
- Substrate concentrations were varied, including levels below and above critical micelle concentrations.
- The effect of deoxycholate on enzyme activity was assessed for different lecithin chain lengths.
- pH profiles of enzyme activity were examined.
Main Results:
- Phospholipase C exhibited significant activity towards mono-molecularly dispersed short-chain lecithins, following Michaelis-Menten kinetics.
- Discontinuities in rate versus substrate concentration curves were observed near critical micelle concentrations, with higher rates above these levels.
- Rate increases were noted for short-chain lecithins below their critical micelle concentrations over extended reaction times.
- Deoxycholate had minimal effect on hydrolysis of lecithins ≤ C8 but significantly increased rates for those > C10.
Conclusions:
- The study demonstrates that Bacillus cereus phospholipase C efficiently hydrolyzes short-chain lecithins, with activity modulated by substrate aggregation state (critical micelle concentration).
- Substrate chain length and the presence of bile salts like deoxycholate significantly impact enzyme kinetics and efficiency.
- These findings provide insights into the substrate specificity and catalytic mechanisms of phospholipase C.