precipitating proteins w/ ethanol

Peter pxpst2 at unixs.cis.pitt.edu
Mon Mar 8 08:56:50 EST 1999

In article <36DF1563.BF89D47D at virtu.sar.usf.edu>, Katherine Walstrom
<kwalstro at virtu.sar.usf.edu> wrote:

> I have some dilute protein samples that I need to concentrate and run on
> an SDS-PAGE gel.  I can't find a detailed protocol for precipitating
> proteins, although what I've read suggests that ethanol works well.  I
> want to precipitate all the proteins, not just selectively precipitate
> some of them.

The best method for recovery of dilute proteins is to use phenol ether
extraction.  I can without much problem, recover 10 ng from 1ml of aqueous
solution and it is not selective.  It works great on all proteins.  TCA,
acetone and ETOH are selctive and only work with relative high amounts of
protein.  Another problem with precipitation is that sometimes you you are
not able to resolvate your protein following the preciptaion.  TCA is
notorious for this because it is a potent dehydrator(sp?)


" Don't you eat that yellow snow
     Watch out where the huskies go"

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