Ammonium sulfate precipitation from solutions with high sugar content

[Michael Sullivan]

What do you want to use the protein for?

I had a very dilute, yet viscous extract of flowers that I wanted to use for western blotting. Carbohydrates made it visous, interfered with protein assays, and made the samples run quite poorly in a gel. I ended up using a phenol extraction method followed by MeOH precipitation that worked quite nicely. Of course, if you are trying to recover active protein this could be a problem.

Mike
---
Michael L. Sullivan, PhD
Research Molecular Geneticist
US Dairy Forage Research Center
1925 Linden Drive
Madison, WI 53706
608-890-0046 (Phone)
608-890-0076 (FAX)

On Apr 30, 2012, at 2:52 AM, WS wrote:

> Dear Experts,
> 
> I am attempting to precipitate small amounts of (total) protein from a
> fruit juice concentrate. It looks quite much like honey. My plan is to
> dilute it 1x with water (to reduce viscosity) and then saturate it
> with ammonium sulfate. As the solution contains high amounts of sugars
> (mostly saccharose, I assume), will these interfere with my
> precipitation process?
> 
> If yes, what may I do to circumvent it? Probably dialysis, but any
> other ideas?
> 
> Thanks for your help!
> 
> Wo
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