please suggest me
I extracted a peptides from herbal plants and lyophilized them.
For minimal inhibitory concentration (MIC) determination, which buffer and at what pH can be used to prepare the stock solution of the peptides keeping in mind that this buffer should maintain the activity of the testing peptide and NEVER act on the testing organisms.
Dear Mohammed Alsaiqali
It is somewhat difficult because either protein activity and microbial growth are affected by pH. But I think that neutral pH range (6-8) could be indicated. So, prepare different phosphate buffers (pH 6 to 8) and make a preliminary study on the effect of pH on your protein activity. Then, select the best buffer and test it on microbial growth. If the effect is significant, choose the second best buffer and test again: you will find a compromise.
Now you could perform the MIC assay using the selected buffer as control.
Regards!
NOBOSSE
thank you Mr. Pierre Nobosse, your suggestion is very good but
Do you think phosphate buffer saline with pH 7.4 will work better or sodium phosphate buffer with the same pH or slightly higher upto 8.0.
thank you.
PBS is more appropriate for assays including living cells. But for pH I think it should be check in situ because of the intrinsic properties of proteins.
Regards!
NOBOSSE
Hi,
Mr. Alsaiqali for the propagation of bacteria tonicity is also a very critical point to be considered. For sure 1X PBS is isotonic and far better option than simple phosphate buffer of same pH range.
You can also try the HEPES buffer as it has a pKa value of 7.5 and HEPES is a better buffering medium than Sodium or Potassium phosphate buffers.
Please do check the osmolarity of your buffer before you proceed with your experiment.
Thanks
Hi,
thank you Mr. Pierre Nobosse, and Mr. Gurav SHarma, for your valuable suggestions.
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