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How does glycogen in DNA precipitation work? - (Ethanol, sodium acetate and glycogen precipitation) (Dec/13/2005 )

Does anyone know how glycogen works in precipitating DNA?

I am using it in an ethanol precipitation procedure from Beckman Coulter for fragment analysis of TRFLPs.

Beckman recommends adding 0.25 ul glycogen per reaction - this is too small to add individually so I have been mixing up a master mix with the glycogen (0.25 ul/rxn) + 0.5 ul NaOAc (3M, pH 5.2) + 10 ul 95% EtOH. My results have been spurious at best. I'm wondering if glycogen should not be added to the master mix, or maybe the EtOH should not be added to the master mix.

Any suggestions?

Thanks so much.

-cja-

If 0.25ul is too little to add, make a 1/2x dulition of glycogen and add 0.5ul?

-Captain_DNA-

hi
what is the concentration of your glycogen stock?
i use 1┬Ál of glycogen 100mg/ml to precipitat 1ml solutions...

-fred_33-

Basicallt glycogen works by acting as a carrier for the DNA. If you add it to the ethanol all you will do is preciptate out the glycogen first. Add it to the DNA then add the ethanol.

-RWhity-

The glycogen is 20 mg/mL.

Thanks for the information - I will no longer make a complete master mix!

-cja-