Why 150 mM KCL in homogenization buffer - (Oct/10/2008 )

Hi.

I see some journals use hight K+ in homogenization buffer (150 mM kcl), not the commonly used NaCl. I am wondering why. thanks

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in this case, K+ seems to have a more effectory potency on your proteins of interest than Na+; losing K+ during homogeneization by high Na+ may alter the structure of some of these proteins...

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Do you mean in high K+, the protein is more soluble?

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in more acurate, functional conformation...

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Thanks

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hm...thanks...so I think I'm gonna replace NaCl with KCl in my buffers too, if as you say K+ really saves conformation better. because I'm working on Bax which its conformation changes during apoptosis.

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to avoid a misunderstanding: high K+ during preparation seems to be relevant for some but not all proteins; if there are no concrete recommendations for a buffer, try a buffer with Na+ in excess over K+

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another reason to use kcl instead of nacl is if you are using phosphate buffers in relatively high concentration and at low temperatures. naphos is less soluble at low temperatures than kphos and will crystallize.

also

in ion exchange chromatography, kcl is stronger than nacl.

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