Concentrating protein lysates

Dr Engelbert Buxbaum via methods%40net.bio.net (by engelbert_buxbaum from hotmail.com)
Fri Jul 3 12:19:05 EST 2015


In article <ba8823a8-e4fe-4749-97c1-b2f6ab079849 from googlegroups.com>,
bimjhanabishwokarma from g.harvard.edu says...
> 
> On Monday, July 2, 2007 at 7:27:59 AM UTC-4, Angela Alexander wrote:
> > I'm working with a new cell line that's giving me very dilute
> > lysates
> >   
> > Speedvac'ing might be reasonable, as we have one in my lab right
> > behind my bench, but I'm concerned the length of time the lysate
> > will not be kept cold that will be required might not be such a
> > great idea. Is dialysis the only way to go, 

You can use the SpeedVac as the sample is kept cold by the evaporation
of water. Just stop as soon as all water is evaporated. 

However, you may find chloroform/methanol precipitation (Wessel & Flügge, 
Anal. Biochem. 138 (1984) 141-3) or precipitation by TCA with DOC as 
carrier (Bensadoun & Weinstein, Anal. Biochem. 70 (1976) 241?50) much 
simpler. 

For larger samples dialysis against solid PEG is very effective (just 
cover the dialysis bag with PEG 20K), but make sure that you do not allow 
the sample to dry out completely (it's usually not possible to 
reconstitute if that happens).

And of course, there are always centrifugal concentrators and (again, for 
larger volumes) Amicon ultrafiltration cells (now flogged by Millipore, 
IIRC).


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