Concentration of dilute proteins for SDS-PAGE
hroychow at NMSU.EDU
Mon May 6 10:00:03 EST 1996
On Fri, 3 May 1996, Joe Stains wrote:
> Does anyone know of any efficient way of concentrating large volumes of
> a dilute protein (several mls) for use with SDS-PAGE? I have a couple
> of ideas on some techniques, but would be interested in anything anyone
> else may have, as they all have a lot of pros and cons!
> Thanks in advance
> Joe Stains
Tha following are a few of the may ways, without the use of commercially
1. Precipitation with 90% ammonium sulfate- brings down almost 95% of the
proteins. Dialysis against a low salt buffer required.
2. Precipitation with acetone. The acetone conc. to be determined
3. Pptn with TCA. A part of the ppt. will not resolubilize, most proteins
would dissolve back into Laemmli sample buffer and the resulting SDS-PAGE
pattern would be fairly representative.
4. EtOH pptn. works the same way as the TCA pptn., and is less harsh.
But, a good percentage of the proteins may not ppt. in alcohol.
5. PEG 8000. This is my favorite. But, the salt concentration also
increases so one may need to carry out drop dialysis before preparing
sample for electrophoresis.
Hiranya S. Roychowdhury
Plant Genetic Engineering Lab.
Box 3GL, NM State Univ.
Las Cruces, NM 88003
Phone: (505) 646-5785
hroychow at nmsu.edu
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