| 摘要 |
PURPOSE:The filtrate of the culture mixture of Thermus thermophilus HB8 is diluted with water until the concentration of inorganic salt reaches a specific level, then, an anion-exchange substance is added to the diluted filtrate to adsorb the heat- resistant exonuclease, which is recovered to isolate said exonuclease in high recovery. CONSTITUTION:Water is added to the filtrate of the culture mixture of Thermus thermophilus HB8 to dilute the filtrate so that the concentration of inorganic salts becomes less than 0.5M. An anion exchange substance such as diethylaminocellulose is added to the diluted filtrate so that the concentration of the ion exchanger becomes 1-100g/l. They are stood at room temperature for 10 minutes to several hours and the anion exchanger is separated by filtration. The anion exchanger is combined with a buffer solution to extract the heat-resistant exonuclease. The extract is combined with ammonium sulfate in an amount of 80% saturation and stood at low temperatures for several hours to several days. The precipitate formed is dissolved in a buffer solution, dialyzed to remove precipitates and subjected to anion exchange column. The fractions of NaCl concentration 0.05-0.1M are collected, dialyzed and concentrated to give said exonuclease. |
