determining DNA extinction coefficient???

Joe Hilario U51141 at
Tue Oct 15 23:56:35 EST 1996

if one is working with a random length ssDNA such as poly(dA)
from Sigma, how would one estimate the extinction coefficient of the
DNA under the following constraints, that you do not know the
length of the poly(dA), and you can not accurately weigh the lyophilized
DNA (microgram amounts) so you can not construct an Absorbance vs.
concentration (micrograms/ml) with enough confidence in your concentrations???

any ideas??

is is it possible to use the factor that an A260 = 1 can be estimated
at 37 micrograms/ml ???   if so then you would have a general
extinction coefficient value of 1/37 ml/microgram for all ssDNA and this
is not true because in reality the extinction coefficient increases
with bases???

so what is the best way to determine the extinction coeff. of random
ssDNA then???


Joe Hilario                             University of Illinois at Chicago
jovencio at                        Department of Chemistry
joe at
jovencio at

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