Isolation and Purification of Ascorbate Oxidase from Acremonium sp.HI-25

概要

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A screening test was undertaken to isolate microorganisms that produced ascorbate oxidase. The enzyme activity was found in a culture filtrate of a fungal strain (HI-25), newly isolated from a soil sample. Based on the morphological characteristics, this isolate was identified as Acremonium sp. From the examinations of cultural conditions, optimum conditions for enzyme production were found ; strain HI-25 was aerobically cultured by a jar fermenter at 25℃ in a medium containing 5% glycerol, 2% defatted soybeans, 0.1% monosodium L-glutamate, 0.1% KH_2PO_4,0.02% MgSO_4・7H_2O, and 0.01% KCl, pH 6.0. After cultivation, an ascorbate oxidase was purified from the culture filtrate by an ammonium sulfate fractionation, column chromatographies on DEAE-cellulose and Butyl-Toyopearl, and gel filtration twice on Sephadex G-100. The purification was 850-fold with an activity yield of 8.8%. The purified enzyme gave a single band on SDS polyacrylamide gel electrophoresis, and had a molecular weight of 80,000 by SDS polyacrylamide gel electrophoresis and 76,000 by native gel filtration. This enzyme was most active at pH 4.0,45℃, and was most stable between pH 6.0-10.0 and at temperatures below 60℃.
社団法人日本農芸化学会の論文
1992-06-23