Acid Precipitation

Michael Benedik bchs1b at Elroy.UH.EDU
Wed Jul 22 22:04:34 EST 1992


In article <q2fm66=@lynx.unm.edu>, kim at m44.unm.edu writes:
>Hello group:
>
>Last year, I posted a question about TCA precipitation, and got several useful
>replies.  . . .  I lost them :(
>
>So here are a few questions.
>
>When one filters the acid-precipitated material through a glass filter, does
>the material actually _stick_ to the glass, or is this a simple particulate
>filtration?  If the latter, Why do we use glass?  Is it just for acid
>resistance?
>
>Can acid precipitated nucleic acids be pelleted and washed as a pellet?  How
>hard do they have to be centrifuged for this?  Has anyone tried this before?  I
>would like to try precipitating in 96-well dishes and spinning using a plate
>carrier in my refrigerated centrifuge, but the maximum RCF is about 2500 x g. 
>Does this sound sufficient?
>
>Thanks for your patience.  
>
>Daniel Kim
>KIM at FLOVAX.LANL.GOV
>

Yes, you certainly can precipitate nucleic acids with TCA in a centrifuge.
Standard DNAse assays are based on the efficient removal of large DNA
and the measuring of the acid soluble (small fragments) left in the sup.
I am not sure if you have enough G force for the microtiter dishes or not,
I guess it is worth a try. It may be quite dependent on the DNA concentration,
in fact I would strongly guess that it is.

	---------------------------------------------------
	 Michael Benedik
	 Department of Biochemical and Biophysical Sciences
	 University of Houston
	 INTERNET: Benedik at UH.EDU	BITNET: Benedik at UHOU



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