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A heme-containing ascorbate oxidase from Pleurotus ostreatus
1Laboratory of Biophysics, Department of Microbiology, College of Natural Sciences, and Research Center for Molecular Microbiology, Seoul National University, Seoul 151-742, Republic of Korea.
The Journal of Biological Chemistry
|February 9, 1996
Summary
A novel hemoprotein ascorbate oxidase was purified from Pleurotus ostreatus mycelia. This enzyme catalyzes ascorbic acid oxidation, showing properties similar to b-type cytochrome.
Area of Science:
- Biochemistry
- Enzymology
Background:
- Ascorbate oxidase enzymes are crucial for various biological processes.
- Characterization of novel ascorbate oxidases can reveal new enzymatic functions and structures.
Purpose of the Study:
- To purify and characterize a novel ascorbate oxidase from Pleurotus ostreatus.
- To determine the enzyme's biochemical and spectral properties.
Main Methods:
- Purification of ascorbate oxidase from cytosolic fraction of Pleurotus ostreatus mycelia.
- High-performance gel permeation chromatography and SDS-PAGE for molecular mass determination.
- Spectroscopic analysis (UV-Vis) and substrate affinity studies.
Main Results:
- A 420-fold purified enzyme with 13% yield was obtained.
- Native enzyme molecular mass of 94 kDa, composed of two 46 kDa subunits.
- Optimal activity at pH 5.2 and 37°C, with Km of 0.48 mM for L-ascorbic acid.
- Spectral data indicated the enzyme is a hemoprotein, similar to b-type cytochrome, containing 2 mol of heme per molecule.
Conclusions:
- A novel hemoprotein ascorbate oxidase was successfully purified and characterized.
- The enzyme exhibits broad substrate specificity for various ascorbic acid forms.
- The findings suggest a role for this enzyme in oxidative processes within Pleurotus ostreatus.