5-FOA solubility

AL R. PLUMMER aplummer at sprint.uccs.edu
Wed Jul 5 15:34:54 EST 1995

Scott Vande Pol (sbv at pop.cwru.edu) wrote:
: We are using FOA (5-floroorotic acid) for selection against URA-3 plasmids
: in yeast.  FOA is expensive to buy and difficult to get into solution. 
: Does anyone know of a non-toxic solvent (such as DMSO) in which a stable
: 100X FOA stock solution can be made?  

: -- 
: Scott Vande Pol
: Case Western Reserve University
: Department of Pathology
: Cleveland Oh. 44106
: sbv at pop.cwru.edu

I know this will sound bad, but I have two methods for getting 5-FOA
into solution: 1)Apply a slight-not high!-amount of heat to your 
5-FOA solution.  I know they say that it is heat labile, but in my
hand it underegoes very little degredation.  2)Raise the pH of your 
solution with NaOH until it goes into solution (Don't use too much
I have used both methods depending on the medium I am preparing:
SD(Glucose) or SG(Glycerol) and have been able to select ura3-
mutants or 'cure' plasmids.

Hope this helps,
			-Al(aplummer at sprint.uccs.edu)

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