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Extracellular poly(3-hydroxybutyrate) depolymerase from Penicillium funiculosum: general characteristics and active
1Department of Chemistry, University of Lowell, Massachusetts 01854.
Archives of Biochemistry and Biophysics
|November 1, 1991
Summary
Researchers isolated a poly(3-hydroxybutyrate) (PHB) depolymerase from Penicillium funiculosum. This glycoprotein enzyme shows optimal activity at pH 6.0 and may be a serine esterase with a critical carboxyl group.
Area of Science:
- Biochemistry
- Enzymology
- Microbiology
Background:
- Extracellular poly(3-hydroxybutyrate) (PHB) depolymerases are crucial for PHB biodegradation.
- Understanding their enzymatic properties aids in developing biotechnological applications.
Purpose of the Study:
- To isolate and characterize an extracellular PHB depolymerase from Penicillium funiculosum.
- To elucidate the enzyme's biochemical properties and active site characteristics.
Main Methods:
- Isolation via hydrophobic column chromatography.
- Molecular mass determination using SDS-PAGE and gel filtration.
- Enzyme kinetics and inhibition studies with various reagents.
Main Results:
- A glycoprotein PHB depolymerase (37,000 Da) was isolated.
- Optimal activity at pH 6.0, isoelectric point of 5.8, Km of 0.17 mg/ml for PHB.
- Inhibition by detergents; sensitivity to DTT and mercuric ions, suggesting a serine esterase mechanism with a disulfide bond and a critical carboxyl group.
Conclusions:
- The Penicillium funiculosum PHB depolymerase exhibits unique characteristics compared to bacterial counterparts.
- The enzyme's properties suggest potential for applications in PHB recycling and modification.
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