Cation exchange - lysin from PBCV1 virions
Purifed PBCV was diluted 2x with K-MOPS buffer (pH7), brought to 2.5mM in EGTA and 1M in LiCl and incubated 15 min at 37. The sample was centrifuged 30min at 25K. The clear supernatant was withdrawn and diluted 3x with K-MOPS buffer. 40 microliters of 2.5 mg/ml polyethylene imine was added. No precipitation was obvious. Nonetheless the sample was centrifuged 5 min at 15K in the microfuge. The supernatant was applied to an Acrosep S (cation exchange) column. The bulk of activity and protein eluted in the flow through volume.
Conclusions:
PEI unnecessary
Apply to column at lower salt concentration
