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Purification and characterization of an extracellular protease produced by Pseudomonas fluorescens M3/6
K L Kohlmann1, S S Nielsen, M R Ladisch
1Department of Food Science, Purdue University, West Lafayette, IN 47907.
Abstract:
Pseudomonas fluorescens strain M3/6 was inoculated into reconstituted NDM and incubated at 7 degrees C for 46 d. A significant amount of extracellular protease was produced, mainly during the latter part of the culture's life cycle. The protease was purified using ammonium sulfate fractionation, ion-exchange chromatography, and gel filtration. The isolated protease had activity on azocasein, alpha-, beta-, and kappa-caseins and a plasmin substrate but did not have plasminogen activator activity. The protease had a molecular weight of 45 kDa, an isoelectric point of pH 8.25, a broad temperature and pH range for activity, and was less heat stable in the isolated form than in the cell-free extract.
Insights
Pseudomonas fluorescens M3/6 produced significant extracellular protease during incubation. This purified protease showed broad activity on various substrates but lacked plasminogen activator activity.
Area of Science:
- Microbiology
- Enzymology
- Biochemistry
Background:
- Pseudomonas fluorescens is known for producing various enzymes.
- Extracellular proteases play roles in microbial ecology and biotechnology.
Purpose of the Study:
- To characterize the extracellular protease produced by Pseudomonas fluorescens strain M3/6.
- To investigate the properties and substrate specificity of the purified enzyme.
Main Methods:
- Inoculation of Pseudomonas fluorescens M3/6 into reconstituted NDM and incubation.
- Purification of extracellular protease via ammonium sulfate fractionation, ion-exchange chromatography, and gel filtration.
- Enzyme activity assays using various substrates including azocasein and caseins.
Main Results:
- Significant extracellular protease production observed during the later stages of culture.
- Purified protease (45 kDa, pI 8.25) exhibited activity on azocasein, alpha-, beta-, kappa-caseins, and a plasmin substrate.
- The protease demonstrated a broad pH and temperature activity range but was less heat stable in isolated form.
Conclusions:
- Pseudomonas fluorescens M3/6 secretes a novel extracellular protease with broad substrate specificity.
- The enzyme's characteristics suggest potential applications in industrial processes requiring protease activity.
- Further studies are warranted to explore its biotechnological potential and detailed enzymatic mechanisms.