In article <mailman.70.1325623817.3721.meth...@net.bio.net>,
hroyc...@nmsu.edu says...
>
> Since you say you have few questions, I am assuming that you are quite
> certain about your composition. PBS stands for "Phosphate buffered
> saline" so it is NaCl, not KCl. Usually we use Na-salts for the
> phosphate combination. Potassium phosphate and -biphosphate may be
> used, but for all practical purposes it is Na- that is preferred since
> lot of compounds do not go well with K+
Actually no - PBS (in the strict sense) is designd to resemble the
extracellular fluid, and hence contains both Na and K:
mM g/l
NaCl 137 8.01
KCl 2.7 0.20
Na2HPO4 ? 2 H2O 10 1.78
KH2PO4 2.0 0.27
Depending on application, Mg and Ca may also be added (e.g., Dulbecco's
PBS). Even closer to extracellular fluid is the Krebs-Henseleit
solution, which also contains glucose and bicarbonate.
Btw, if one wants to work with intracellular enzymes, PBS should not be
used, and replaced with a high K, low Na medium!
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