Ammonium sulfate precipitation from solutions with high sugar content

Irit Rappley via (by irappley from
Mon Apr 30 23:52:18 EST 2012

Hi Wo,

In the past I've added 1 mg/mL BSA to a dilute protein solution, then precipitated it with TCA. However, then you'll be stuck with 1 mg/mL BSA in your resulting pellet. 

If you're seriously considering the 24 eppis option, wouldn't dialysis be easier?


From: methods-bounces from [methods-bounces from] On Behalf Of WS [novalidaddress from]
Sent: Monday, April 30, 2012 2:22 PM
To: bionet.molbio.methds-reagnts from
Cc: methods from; WS
Subject: Re: Ammonium sulfate precipitation from solutions with high sugar      content

Hi Pow, long time no see :)

My big problem is that there is almost no protein in the sample -> I won't see any bands. I expect about 1mg from 50 ml. I have started with 50ml of fruit juice concentrate, diluted with 50ml water and then added ammonium sulfate until saturation: No visible turbidity, No (visible) pellet after 2hrs @ 4000g (except some ammonium sulfate crystals. Unfortunately, I do not have access to a high speed centrifuge for such volumes. Spinning 24 eppis with 2ml each @ 15.000g in my small benchtop centrifuge might be an option, however.

Could it make sense to add some unrelated protein, eg BSA or OVA (that's what I have in my fridge), as co-precipitant (like one does with glycogen or poly-acrylamide for DNA)?.


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