DNAse at pH5?
graham at biodec.wustl.edu
Wed Jun 12 17:25:30 EST 1996
There is a legacy here whose source I cannot unearth -that total
RNA samples be treated with DNAse at pH 5 rather than neutral pH to
eliminate contaminating DNA.
All I have seen so far is that Boehringer gives their DNAse activity
units in terms of action in a pH5 buffer, and that indeed my RNA
emerges from such a DNAse treatment intact, while not fairing at all
well when treated at a more conventional pH (8.0). I have no idea yet
what kind of DNA removal this former treatment achieves, being a pH at
which only some 10-20% of DNAse I activity would be expected to remain.
Perhaps residual endogenous RNAses are differentialy inhibited
to a greater extent than DNAse at this pH? Is it a typo? :)
J. Graham PhD
Washington University of St. Louis
(PS. Not interested in binding matrices or proprietary columns suggested
to selectively eliminate DNA- but might like to hear about other approaches.)
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