use of glucose in plasmid isolation

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ddee's picture
use of glucose in plasmid isolation

Hi all

I have a doubt regaring the use of the glucose in solution I . What is the exact role of glucose ?
After searching a lot I could find that it maintains the omsotic potential of the bacterial cells but i donot understand how does it maintain that?

Can anyone help me?

Thanks in advance

RLS's picture
 I posted this in a previous

 I posted this in a previous forum:

There is a narrow range of pH (~12-12.5) in which linear DNA is denatured without denaturation of the covalently closed circular, aka plasmid, DNA as well. The glucose helps maintain the proper pH during the denaturation/cell lysis step.

If you are interested in learning more about this, take a look at the original paper on alkaline lysis for more information: 

Birnboim, H.C. and J. Doly. 1979. A rapid alkaline extraction procedure for screening recombinant plasmid DNA. Nucleic Acids Res. 7: 1513.

Hope this helps.