| 摘要 |
PURPOSE:To obtain a completely homogeneous enzymic sample with excellent reproducibility, by carrying out special treatment, such as crushing of cultivated microbial cells, treatment with streptomycin sulfate and fractionation with ammonium sulfate. CONSTITUTION:Cultivated microbial cells are crushed and centrifuged to provide a supernatant, which is then treated with streptomycin sulfate, fractionated with ammonium sulfate and subjected to operation of butyl Toyopearl(R) column chromatography, gel filtration chromatography and DEAE-Toyopearl(R) chromatography. Escherichia coli transformed with a recombinant plasmid pBSFOL14-1 containing Bacillus subtilis dihydrofolic reductase gene integrated therein is used as the cultivated microbial cells to purify the Bacillus subtilis dihydrofolate reductase. If Escherichia coli transformed with a recombinant plasmid pBSFOLEK1 is used, dihydrofolic reductase-leucine enkephalin fused protein can be purified. |
