Sami Kalliney

An efficient peroxidase-catalyzed oxidation of hydroxylaminoeverninomicin in aqueous-organic media

A horseradish peroxidase-catalyzed oxidation of nitroso- and hydroxylamino derivative of the antibiotic Everninomicin (EVN) by hydrogen peroxide has been carried out. Due to the very low solubility of the substrate in water, the oxidation was performed in 50% aqueous/dioxane mixture. Despite the high concentration of the co-solvent the enzyme remained selective and highly active. The conversion of the hydroxylamino-EVN 1 to nitro-EVN 3 was quantitative and proceeded via the nitroso-EVN intermediate 2. The oxidation with H218O2 indicated that oxygen on the nitro group derived predominantly from the hydrogen peroxide, thereby providing a strong evidence for a direct ferryl-oxygen transfer.

Quantitative thin-layer chromatography of everninomicin D

Abstract A direct densitometric method for the assay of everninomicin D after thin-layer chromatography is described. The fluorescence quenching (transmittance) method and automatic integration of the spot area were used. The peak areas were linear with the amount spotted from 3 up to 40 μg. By direct evaluation of the thin-layer chromatograms, as little as 10 μg of everninomicin D can be determined with a relative standard deviation of 2.3%. The densitometric method was used to follow the course of the fermentation of everninomicin D on a laboratory scale.