| 摘要 |
PURPOSE:To obtain the subject new water-soluble enzymic protein, composed of plural heterosubunits, separated and purified from a bacterium of the genus Rhizobium and capable of manifesting the nitrile hydratase activity and efficiently converting nitriles into the corresponding amides. CONSTITUTION:A bacterium Rhizobium.sp. MCI2643 (FERM BP-3953) separated from soil is cultured in a culture medium at 28 deg.C for 40 hr and the microbial cell is collected by centrifugation, suspended in a buffer solution, ultrasonically crushed render being cooled with ice water and then centrifuged to recover the supernatant. A saturated solution of ammonium sulfate is added to the resultant supernatant so as to provide 25% (wt./vol.) concentration thereof. The formed precipitate is then removed and the saturated solution of ammonium sulfate is further added to the supernatant so as to afford 65% (wt./vol.) concentration thereof. The produced precipitate is recovered and the precipitate is dissolved in a buffer solution, fractionated and purified by column chromatography to provide the objective water-soluble enzyme protein, composed of three subunits, having about 110000 molecular weight (measured by the gel filtration method) and 26000, 15000 and 16500 molecular weights of the subunits (measured by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) method) and the nitrile hydratase activity. |
