[ccp4bb] ion exchange: protein peak also in water!!

[K Singh]

Dear All,
Apologies for bit off-topic. I am in process of purifying a protein by
ion-exchange (cation)
using 0.5-3M NaCl gradient. And I get a sharp peak which is western
positive. Following elution,
I  wash the column  >10 column volume with 3M NaCl. and now when I
wash the column
with water, I get a huge peak which is also western positive. Any
inputs or suggestions explaining
this phenomenon?
Kris