Purification and properties of alcohol oxidase from Poria contigua

1. Alcohol oxidase (alcohol:oxygen oxidoreductase) was purified 22-fold from the brown rot fungus Poria contigua. The final enzyme preparation was homogeneous as judged by polyacrylamide gel electrophoresis, and by sedimentation in an ultracentrifuge. The molecular weight was calculated to be 610000 +/- 5000 from sedimentation equilibrium experiments. Electrophoresis in sodium dodecylsulfate gels and electron microscopic analysis indicate that the enzyme is an octamer composed of eight probably identical subunits, each having a molecular weight of 79 000. The enzyme contains eight mol FAD/mol as the prosthetic group. 2. This alcohol oxidase oxidizes not only methanol but also lower primary alcohols (C2-C4), 2-propin-1-ol and formaldehyde. The apparent Km value for methanol is 0.2 mM, and that for formaldehyde 6.1 mM. Sodium azide was found to be a competitive inhibitor with respect to methanol. 3. The enzyme from the fungus Poria contigua is immunologically different from the alcohol oxidase isolated from the methanol-utilizing yeast Candida boidinii. Furthermore antiserum raised against this enzyme did not cross-react with the alcohol oxidase from the white rot fungus Polyporus obtusus.