When it comes to peptide dissolution, there is no single universal solvent, which can be used to solubilize all lyophilized peptides, while at the same time maintaining their integrity and compatibility in their biological states. Peptides solubility has been a great problem for many people for many years. As of the moment, there are a number of solvents in use, and basically, there are three most common approaches wildly used when it comes to coming up with the various solvents for peptides. They include the following:
Approach 1: Use of sterile distilled water or dilutes acetic solution
The first approach for peptide dissolution involves the use of sterile distilled water or dilutes acetic solution. These solvents are ideal since they provide a higher concentration of peptides. Once diluted with either of the solutions, the solution will then be diluted with an appropriate buffer. With regards to increasing the concentration of the solution, sonication is a viable process.
Approach 2: use of dilute acetic acid, dilute aqueous ammonia or ammonia bicarbonate
These solutions are used when the peptides remain insoluble after the first approach. In such a case, you will have to check the levels of hydropholic, hydrophobic and the change on the neutral pH. If there is a significant change in Neutral pH, then dilute acetic acid or aqueous ammonium or ammonia bicarbonate is added. If this still doesn’t dissolve the peptide, then you should try other alternative solvents recommended for that particular peptide.
Approach 3: Ethanol, acetonitrite, sulphoxide, chaotropic salts
If there is no change in the Neutral pH, then you should use ethanol, dimethylformamide, dimethyl sulphoxide acetonitrite, or chaotropic salts to help in enhancing the dissolution process. For most cases, this should generally work but again, it will depend on the choice as well as the compatibility of the peptides with the reagents.