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Appl. Environ. Microbiol., 12 1997, 4793-4799, Vol 63, No. 12
M Okazaki, T Sugita, M Shimizu, Y Ohode, K Iwamoto, EW de Vrind-de Jong, JP de Vrind and PL Corstjens
The Mn(2+)-oxidizing bacterium Pseudomonas fluorescens GB-1 deposits Mn
oxide around the cell. During growth of a culture, the Mn(2+)-oxidizing
activity of the cells first appeared in the early stationary growth phase.
It depended on the O2 concentration in the culture during the late
logarithmic growth phase. Maximal activity was observed at an oxygen
concentration of 26% saturation. The activity could be recovered in cell
extracts and was proportional to the protein concentration in the cell
extracts. The specific activity was increased 125-fold by ammonium sulfate
precipitation followed by reversed-phase and gel filtration column
chromatographies. The activity of the partly purified Mn(2+)-oxidizing
preparation had a pH optimum of circa 7 and a temperature optimum of 35
degrees C and was lost by heating. The Mn(2+)- oxidizing activity was
sensitive to NaN3 and HgCl2. It was inhibited by KCN, EDTA, Tris, and
o-phenanthroline. Although most data indicated the involvement of protein
in Mn2+ oxidation, the activity was slightly stimulated by sodium dodecyl
sulfate at a low concentration and by treatment with pronase and V8
protease. By polyacrylamide gel electrophoresis, two Mn(2+)-oxidizing
factors with estimated molecular weights of 180,000 and 250,000 were
detected.
Copyright © 1997, American Society for Microbiology
Partial purification and characterization of manganese-oxidizing factors of Pseudomonas fluorescens GB-1
Department of Biology, Tokyo Gakugei University, Japan. okazaki@u- gakugei.ac.jp
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