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Role of Sodium Acetate in DNA precipitation - (Oct/18/2005 )

Hi everyone,

I would like to know what is/are the functions of sodium acetate in DNA precipitation? Why is the pH5.2? I have experience precipitating DNA after phenol:chloroform:IAA (25:24:1) extraction using 3M sodium acetate pH5.2. As soon as I add colded 95% ethanol after sodium acetate (1/10 volume) for DNA precipitation, the whole solution turned cloudy with a lot of white precipitate, precipitating down. Is it the salt or what?

Thanks for all the replies in advance, really appreciate your replies.

Haohao

-haohao-

hi
acetate is negatively charged
low pH contibutes to charge positively the DNA
combination of this plus high salt molarity enhances formation of aggregates of DNA and facilitates the pelleting procedure.

-fred_33-

Thanks a lot fred 33, for you really quick reply. Awesome.

-haohao-

Sodium acetate does not crystallize but inhibits the Klenow fragment

Seb_

-tryptofan-