送交者: Godfather 于 2006-1-20, 13:05:45:
回答: If I was Qiu, I would remove streptomycin from the procedure. 由 fair 于 2006-1-20, 12:36:31:
True. After high speed centrifugation, DNA is no longer an issue for protein purification at lab scale. Even at large manufacturing scale, DNA can be efficiently removed by addition of 0.2% PEI. In fact, the first purification of Colicin Ia by J. Konisky & F. Richards in 1970 did not use streptomycin precipitation. What they used was a 5-step procedure in which the first one was ammonium sulfate precipitation, and later they eliminated the last step of hydroxyapatite column that was not necessary. Therefore, the only reason to keep using streptomycin was intentional unless Dr. Qiu does not have the knowledge or skills on protein purification.