BCA-Protein-Quantification: Time Drive?

[Christoph Peter]

Hi all!

I use the bicinchoninic-acid-assay in a 96well format to
determine/estimate protein concentrations. I always have a
standard-dilution-row on every plate.

When I tried to determine the concentration of a simple yeast-extract,
I noted the following:

- the slope of the calibration-line (mg as a function of A550)
decreases with time (15min to 3hrs)

- the concentration of my extract also decreases with time!!!!
(calculated with corresponding slope!)

As the assay is designed to be read after 30min and 30degrees C - when
do I get the _correct_ concentration?????????????????

MTIA

Christoph
--
Christoph Peter
PhD Student (Biotechnology)
cpeter at zedat dot fu-berlin dot de

>Alles wird gut!<(Beate)