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using CTAB for polysaccharide removal - (May/03/2004 )

Has anyone used CTAB to remove polysaccharide during DNA extraction? I tried to use it under high NaCl, but have had coprecipitation problem. My lysis buffer contains Tris, EDTA, NaCl, and SDS. After solvent extraction, it seems like CTAB will coprecipitate with DNA when I added ice-cold propanol and incubated at -20C. Does anyone know how to prevent this co-precipitation?


Never done this but I know that we never centrifuge CTAB at 4oC. We do it at 9oC otherwise as you said it precipitates and you'll never get rid of it.
Try not using ice cold isopropanol and don't do anything with CTAB below 9oC. Hope it helps. Good luck.


are you sure DNA was coprecipitate with CTAB,
I think it is normal,
only add ethanol, the DNA would precipitate


I believe it's CTAB that was coprecipitated. I was trying to do recovery test and the pellet was way more than what I expected for the amount of DNA added. The size of the pellet was like 100 ul worth and I only put in 10 ug DNA.

Do you mean that I should use alcohol for precipitation in stead of isopropanol?

Thanks for the answers by the way.