Peptide-Tools–Web Server for Calculating Physicochemical Properties of Peptides

Peptides play an increasingly important role in medicine and materials science. Accurate estimation of peptide physicochemical parameters is essential for their design, purification, and analysis. In this manuscript, we present Peptide-Tools, a freely accessible web server with an intuitive user interface for calculating isoelectric points and evaluating common chemical stability liabilities in both natural and modified peptides. Peptide-Tools accommodates a variety of input formats and can account for the ionization states of noncanonical amino acids and other molecular fragments. The platform also computes peptide extinction coefficients at three wavelengths (205, 214, and 280 nm), with this functionality currently available only for canonical amino acids. The server relies on a command-line tool that can be installed locally. We anticipate that Peptide-Tools will streamline peptide optimization and support routine tasks in chemical and analytical laboratories.