The solubility of a polypeptide largely depends on the polarity of the polypeptide.
The acidic protein is dissolved in the alkaline solution, and the basic protein is dissolved in the acidic solution.
In peptide solubilization, hydrophobic and neutral peptides containing a large number of uncharged polar amino acid residues or hydrophobic amino acids can be dissolved in a small amount of organic solvents, such as DMSO, DMF, acetic acid, acetonitrile, methanol, propanol or isopropyl Alcohol, then dilute with distilled water.
Peptides containing methionine or cysteine cannot be dissolved in DMSO because DMSO may cause side chain oxidation.
Peptide solubilization test: Before peptide solubilization, take a small part of peptide solubilization test. You need to test several different solvents until you find the most suitable one. Ultrasonic treatment helps to break up the particles and increase solubility. (Note: Ultrasonic treatment will cause solution heating and peptide degradation.)