Purification of recombinant brain derived neurotrophic factor using reversed phase displacement chromatography

This work investigates the utility of RPLC displacement chromatography for the purification of recombinant brain derived neurotrophic factor (rHu-BDNF ) from its variants and E. coli. protein (ECP) impurities. The closely asso ciated variants (six in total) differ by one amino acid from the native BDN F and thus pose a challenging separation problem. Several operational param eters were investigated to study their effects on the yield of the displace ment process. The results indicated that the concentration of trifluoroacet ic acid (TFA) in the buffer was a key factor in achieving the desired purif ication. Displacement chromatography on an analytical scale column resulted in extremely high purity and yield in a single chromatographic step. The p rocess was successfully scaled-up with respect to particle and column diame ter. The production rate of a pilot scale RPLC displacement process was sho wn to be 23 times higher than the combined production rates of the current preparative ion exchange and hydrophobic interaction gradient elution steps that are used to remove variant and ECP impurities, respectively.