I am working with a series of 13-mer peptides that are quite hydrophobic. Most of the peptides do not contain any acidic or basic residues. The peptides are capped at the ends (N-terminal acetylation and C-terminal amidation). They also contain two Met residues. I have tried pretreating the peptides with HFIP or DMSO, but one or more of the peptides fall out of solution within minutes of adding buffer (10mM phosphate, pH 7.4). I am hoping to study the peptides by CD and Thioflavin T binding.
Dear Kristi,
You may try to enhance the solubility of your peptide using cyclodextrins.
For the use of cyclodextrins in enhancing solubility of different chemical moieties, please see a recent review article contained in the following link:
http://inter-use.com/uploads/soft/160610/1-160610101159.pdf
Hoping this will be helpful,
Rafik
In the past I isolated ribosomal peptidyl deformalase from a B. subtilis lysate and used it to cleave a formyl group from F-Met-Leu-Phe. The enzyme was very unstable; I was unable to preserve any activity for more than a few days. I don't know if this enzyme will be able to handle removal of an N-terminal acetyl group.
Can your experiments tolerate acetonitrile? You might try it as a peptide co-solvent, dissolve the peptide in acetonitrile then add water to see if it precipitates out. If you are careful and keep track of the volumes you will know the minimum concentration of acetonitrile the peptides are soluble in.
I have synthesized peptides that are extremely soluble in diethyl ether and would not dissolve in the presence of any water. I ended up dissolving them in trifluoroacetic acid to get them into solution for automated Edman sequencing.
I worked on a project that used a hydroxypropyl derivative of beta cyclodextrin to solubilize a pharmaceutical peptide. The peptide was soluble at high concentrations but the betcyclodextrin delaminated the glass from the walls of the vials the formulation was placed in.
If you don't want the N-terminal acetylation, you can resynthesize the peptides without it.
If that is not an option, here is a paper describing a chemical method for peptide deacetylation.
http://www.ncbi.nlm.nih.gov/pubmed/9398353
You might be able to keep your hydrophobic peptides in aqueous solutions containing a detergent. Of course, the detergent may interfere with the analyses you wish to perform.
- Badges
- Science topic
- Similar topics
- Chemistry
- Biochemistry