Agarose vs sepharose

Question

Hi,

I would like to do an immunoprecipitation of a rat protein. I have seen papers use either Protein G agarose or sepharose. Can anyone tell me the difference berween these two and how to make the choice?

Thanks,

Shirley

Answer 1

Sepharose is simply a beaded form of agarose.  Though I've not personally used agarose for affinity work, I suspect that sepharose would work a bit better. However, a number of online resources suggest that for IP the two are functionally equivalent.  

You can also use protein G-coupled paramagnetic beads to do the same thing, with claims of very rapid separations (look up dynabeads through Invitrogen).

Choosing between sepharose and agarose is much more important in size-exclusion (gel filtration) chromatography, where agarose has a larger pore size.