Glucose oxidase as the antifungal principle of talaron from Talaromyces flavus.

Analysis of an authentic sample of the antifungal antibiotic talaron from the biocontrol fungus Talaromyces flavus indicated that approximately 40% of the solid sample was glucose oxidase. High-performance liquid chromatography elution profiles of the antimicrobial activity of talaron coeluted with those of glucose oxidase. Fluorescence emission and excitation wavelength maxima for talaron were similar to those of glucose oxidase from Aspergillus niger. The molecular weight of talaron was 152,000 with a subunit molecular weight of 71,000. The isoelectric point of talaron was pH 4.2. Mobilities of talaron on native, sodium dodecylsulfate, and isoelectric focusing polyacrylamide gels were identical with those of glucose oxidase produced by T. flavus. Furthermore, talaron had antimicrobial activity only in the presence of glucose. Hydrogen peroxide produced by the action of glucose oxidase is toxic to Verticillium dahliae. This study indicates that the antifungal activity of authentic talaron resulted from glucose oxidase produced by T. flavus.