2
votes
2answers
43 views

pI and pH relationship in context of ion exchange protein purification

I am confused about relationship between isoelectric point and pH in context of ion exchange protein purification. Why we cannot use this method for protein with pI below 7? Thank you very much for ...
2
votes
1answer
56 views

How to identify active protein in a complex mixture?

I am trying to figure out how to identify which protein in a complex mixture is producing a certain effect. There is an assay for the effect, so anything (a fraction of the mixture) can be tested ...
3
votes
1answer
111 views

How to wash the column during protein purification with GST tag?

I have been working with GST tagged proteins for the last 4 years and after loading the cell lysate into the column I was washing it with 20-30 column volumes of PBS and sometimes my proteins were ...