Concentrating protein lysates

AK via (by akhan357 from
Mon Jul 2 15:28:02 EST 2007

Angela, you might want to try ultrafiltration. Amicon (now i think part of 
millipore) should have many choices.  basically, you start with lets say 2ml 
of ur lysate and can concentrate down to 50ul in relatively short time. this 
is centrifugation based so no problem with temp. these units will come in 
mol.wt cut offs, which means u choose one which will not let your protein of 
interest pass through the membrane.

Also, what I have done in past (it is cheating i know!) is to let the sample 
compact in stacking gel, then load again. the second load will catch up to 
the first with sharp bands. this require u make ur stacking get just a bit 

hth, good luck

"Angela Alexander" <udflutes from> wrote in message 
news:mailman.165.1183398400.11350.methods from
> I'm working with a new cell line that's giving me very dilute lysates 
> (even with a vastly reduced volume of lysis buffer), such that I can 
> barely load 15-20 micrograms of protein on a western gel. I'm doing a lot 
> of signaling analysis and sometimes need more protein than that to get 
> solid blots for some phospho-antibodies (we usually load 30-40). So I was 
> wondering if you guys had any suggestions on the best method for 
> concentrating my lysates without affecting my data ie losing robustness of 
> phosphorylation.
> 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, or is there a quicker, easier method?....since I will be 
> generating many long time courses/dose responses with these cells once I 
> figure out the best method/something that works.
> Thanks
> Angela Alexander
> Graduate Student
> University of Texas MD Anderson Cancer Center
> ---------------------------------
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> TV. 

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