Hi all,
I only wish to draw your attention to the fact that the
Henderson-Hasselbach equation (as used in the paper you cite) is only
valid if you use zwitterionic buffers. Otherwise, with other buffers,
especially phosphate and multi-acids (e.g. succinate, citrate and so
on), any calculation using the Henderson-Hasselbach equation must refer
to activities and not concentrations.
Given this, expect a phosphate buffer pH to increase by 0.3-0.4 units
upon a 10-fold dilution (That is from 1.0M to 0.1M in the referenced paper).
Regards,
Pr. Nadir T. Mrabet
Cellular & Molecular Biochemistry
INSERM U-724
UHP - Nancy 1, School of Medicine
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Jose M de Pereda wrote:
Hi Jenny (and others),
The buffer systems used in the PACT screen are described in the
following paper by Janet Newman.
/Acta Cryst./ (2004). D*60*, 610-612 [
doi:10.1107/S0907444903029640
<http://dx.doi.org/10.1107/S0907444903029640> ]
Novel buffer systems for macromolecular crystallization
J. Newman
<http://scripts.iucr.org/cgi-bin/citedin?search_on=name&author_name=Newman,%20J.>
I am not aware of any commercial source of these buffer systems. But
the paper describes the recipes to make them, which is quite easy.
HTH
Jose
On 30/01/2007 5:19 Jenny wrote:
Hi,
Sorry to bother you all.I'm going to try to reproduce some results
from the initial screening from PACT kit.The conditions are something
like 0.1M PCB buffer, 25% w/v PEG 1500 and 0.1 MMT buffer, 25%w/v PEG
1500. I was just wondering is there any easy way to get these
buffers?Do you happen to know where to order?Or I have to order the
component formula separately and then make buffers by myself?Thanks.
Jenny
