Often the exact concentration is not so important compared to the
ability to establish proportional read-out, ease and reproducibility
so that systematic variations and comparisons can be made. For
considerations of molar ratios of for example protein:ligand complexes
one would often screen a range or add in excess in any case, so
probably again you are fine. For an accurate calibration of your
method of choice you can opt for a total aminoacid analysis.
Poul
On 21/08/2008, at 15.07, Puneet juneja wrote:
Dear Mark
Most easy way to have relative estimation is to run PAGE of your
protein with known proteins of known different concentration so u
can have a good relative estimation.
but for more accurate estimation u can go for Biochemical methods
such as Lowry method or BCA method which are more senstive then UV
spectro method although they depend upon oxidation of total
aromatic amino acid in protein u can try or wait for other
suggestions.#
.
Puneet Juneja
On Thu, Aug 21, 2008 at 12:54 PM, Mark Hilge <[EMAIL PROTECTED]> wrote:
Dear all,
I would be glad to hear what (simple) method I should use to
determine protein concentrations as accurately as possible.
Presently, I'm measuring absorption at 280nm with a nanodrop device.
I either have 0 or 1 tryptophan and no activity test.
Many thanks in advance!
Best regards,
Mark
Mark Hilge
Protein Biophysics
NCMLS 274
3rd floor M850.03.035
Geert Grooteplein 28
6525 GA Nijmegen
The Netherlands
http://www.mark-hilge.com
Phone: 0031 24 36 10 525
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