At 10:53 PM 9/19/97 GMT, Stephen C. Dahl wrote:
>Damn this server....somebody wrote:
>>: How do I concentrate a low molecular weight protein (less than 5kDa)
>: from gel filtration fractions ie. dilute???, keeping in mind that
>: filtration devices and dialysis tubing concentrate above this size.
>>>One option which I've used on a limited basis (and have never taken the
>time to quantify the results) is to swell a powdered gel filtration
>medium--in your case Sephadex G10 or G15--in your pooled fractions. The
>beads take up the water and, in general, exclude your protein if you
>choose your matrix wisely. Good luck.
I wonder if extracting the protein solution with something like n-butanol
will do the trick too. I have used it to concentrate DNA solutions. But
then, some proteins may ppt in that solvent. If this one doesn't, then
surely n-butanol extraction is worth a try. The other alternative is to use
a volatile buffer (eg. bicarbonate) in protein elution and then to
freeze-dry the sample.
Dr. Hiranya Sankar Roychowdhury
Plant Genetic Engineering Lab.
New Mexico State University
Las Cruces, NM 88003
Ph. (505) 646-5785
hroychow at nmsu.edu