David L. Haviland, Ph.D. dhavilan at IMM2.IMM.UTH.TMC.EDU
Wed Mar 18 10:36:15 EST 1998

At 11:16 3/18/98 GMT, 3Dom wrote:
>i'm looking for the reference ( MElton and Al  1984 ... ???? ) that talk
>about the precipitation of DNA with PEG. if you have the complete ref  i
>want it.
>Do you have compare PEG-NaCL ( 13 % in final ) and  PEG-MgCL2 and do you
>think that a scale up is possible when you use a PEG (30 % ) in MgCl2 10
>mM. applied in this article ( biotechniques vol 14 /4  1993 , p 534-536

I'm not sure what you're trying to do but the recipe in Nicoletti &
Condorelli B_Tecniques 14:532 calls for 1/2 volume of 40% PEG 8000/30 mM
MgCl2.  When made correctly, yes, it can be scaled up depending upon the
final volume.  

This and other PEG  related references tell you that you can achieve
differential preciptiation depending upon the components added to the PEG
solution.  From my own experience, I'll agree with Nicoletti & Condorelli,
if you want to precipitate as much as you can above 120 bp *consistiently*,
then stay with the PEG/MgCl2 recipe.

 David L. Haviland, Ph.D.
 Asst. Prof. Immunology 
 University of Texas - Houston, H.S.C.
 Institute of Molecular Medicine  
 2121 W. Holcombe Blvd.  
 Houston, TX  77030 
 Internet:"dhavilan at" 
 Voice: 713.500.2413  FAX: 713.500.2424
Never take life seriously. Nobody gets out alive anyway.

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