Size-Fractionation of DNA

William Alexander ALEXANDERW at
Wed Oct 18 05:33:22 EST 1995

Try using the Amicon microcon spin filters to get rid of SS and DS RNA/DNA
below 300 bases or 125 bp.  There are different filters for different
molecular weight cut offs.  Amicon also has a fax back sevice to send
protocols for desalting, size seperation, etc. (no affiliation)  They may
cost a little but they are fast and you can avoid creating phenol waste,
which costs $ to dispose of.


Bill Alexander

In Article <Pine.SUN.3.91.951018084008.3974A-100000 at chuma>,
leverone at CHUMA.CAS.USF.EDU ("Marianne Leverone ", BIO) wrote:
>Bob:  I have used a CL-4B column to remove RNA from plasmid preps and the 
>method worked well with high yields.  I don't know about the size limits of 
>this matrix.  Look in a catalogue that sells the stuff and it will tell 
>you what sizes of DNA that can be isolated.  I always thought that it 
>could not be used to size fractionate DNA, say for producing a library, 
>because the plasmid isolation was based on the plasmid not getting 
>trapped in the matrix but smaller, linear pieces did get trapped.  How 
>about it gang?  Does anyone else know?  Marianne Leverone, Biology Dept., 
>Univ. of South FLorida, Tampa, FL.
>On Mon, 16 Oct 1995 colvin at wrote:
>> Before subclonning ds DNA generated by PCR into a plasmid, I would like to 
>> remove small DNA fragments.  The template used for PCR was a subtracted cDNA
>> library, so there are many different sized fragments present.  One method
>> that I am aware of is to use a sepharose CL-4B column.  Have others used this
>> method with success?  Are there other methods that are simple, but still give
>> good recovery?  Thank you.
>> Bob Colvin, Dept. Biological Sciences, Ohio Univ. Athens, OH, USA
>> colvin at

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