Predicts protein solubility. Protein-sol returns the predicted solubility and other properties of an amino acid sequence in a graphical format. It was demonstrated with E. coli thioredoxin, known to enhance solubility of co-produced proteins in E. coli. The tool is able to highlight lysine and arginine content in regard to modifying protein solubility. It can interpret subdomain structures and introduces the feature of windowed net charge, which may inform on charge-charge interactions between subdomains.