35S-labelled oligo purification

[Dr. Duncan Clark]

In article <8791g0$2mj$1 at beta.qmw.ac.uk>, News
<D.P.McLaughlin at mds.qmw.ac.uk> writes
>The oligos are HPSF pure synthesised by MWG biotech - no problems in the
>past and EtOH
>precipitation works well - just looking for a quicker method.  Pharmacia
>(Amersham)
>assure us that the unincorporated 35SdATP will wash off the column, but that
>the
>interacton with the 35S labelled oligo is 'ionic'.  Trouble is, we can wash
>off the
>unincorporated 35S after a few washes, but the labelled oligo sticks until
>vortexed
>vigorously and then eluted.  It is all very puzzling since the product
>guides for all
>their microspin columns suggests G25 for labelled oligos

Am I missing something here? How are you labelling oligos with 35S dATP?
Are you not kinasing using T4PNK and gamma labelled 35S ATP?

Duncan
-- 
The problem with being on the cutting edge is that you occasionally get 
sliced from time to time....

Duncan Clark
DNAmp Ltd.
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