A high-yield chromatographic method for the purification of rat fibroblast interferon to a high specific activity.

Rat fibroblast interferon (RfIFN), produced in serum-free media, has been purified 2,000-fold to 88% purity by a simple method that involves only two chromatographic steps: controlled pore glass and phenyl agarose chromatography. Over 70% of the initial activity was recovered. Gel electrophoresis (SDS-PAGE) and silver staining of the purified RfIFN revealed two major bands of RfIFN activity corresponding to Mr of 26,000 and 22,500 daltons, respectively. A very small amount of RfIFN was also recovered from a region of the gel corresponding to a Mr of 18,500. The average specific activity of the purified material was 3.7 X 10(8) U/mg. From these results it can be calculated that the specific activity of homogenous RfIFN is 4.0 X 10(8) U/mg.