Sodium or Ammonium?

Hiranya Roychowdhury hroychow at NMSU.EDU
Thu Jun 26 11:21:18 EST 1997

At 08:15 PM 6/24/97 GMT, Richard L wrote:
>Dear colleagues,
>I want to recover soem DNA fragments from gels for cloning, but I don't
>know which salt, sodium or ammonium acetate, should be used to
>precipaitate DNA (along with ethanol). Some people say ammonium aceate is
>more effective for precipitation, but the trace of ammonium will inhibit
>the ligation reaction, is that true?
>Thanks a lot

Any one of those is fine. The Amm salt is used to keep out very small pieces of NA and/or Ntds. Also, it is easily removed from the ppt. being more hygroscopic/hydrophilic and volatile. Ammonium ions inhibit kinase reactions and not the ligase reaction.

Dr. Hiranya Sankar Roychowdhury
Plant Genetic Engineering Lab.
New Mexico State University
Las Cruces, NM 88003
Ph. (505) 646-5785
hroychow at

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