I have a peptide with high hydrophobicity commonly dissolved in DMSO. However there's noise generated by DMSO background when analyzed by CD spectra. Any suggestions on choosing a proper solvent? Thanks!
It is depends also from the hypotetical secondary structure of your peptide.
You can use mix of water and non polar solvent.
If your peptides is predicted to have an alpha elix ocnformation you can use TFE (trifluoroethanol). You can find a lot of articles related to this solvent.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2143935/
One other possibility is use weak detergents used normally for membrane protiens as OG, DM, DDM
http://www.sciencedirect.com/science/article/pii/S000527361200017X
in this case i think that the best idea is that before starting the experiement with the peptide you analize some buffer samples , containing different concentration of each detergent to assess if there is a maximun concentration that you can use in the CD.
good luck
Manuele
Background noise, particularly at low wavelengths, is a common problem with all these solvents. Testing buffers is a right suggestion. In my experience a mix of ethanol (spectroscopic grade) and purified water might be the best choice. Of course you have to test the best concentration ratio. Another consideration is the peptide length. Few amino acids (up to 7 - 8) behave differently from longer peptides.
have a good day
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