Peptalyzer

Peptalyzer™ is a free web calculator for synthetic peptide chemists. From a sequence it computes monoisotopic and average mass, net charge and isoelectric point on several pKa scales, hydropathy profiles (GRAVY, Kyte–Doolittle, Hopp–Woods, Wimley–White), extinction coefficients, aggregation and secondary-structure risk, MS precursor and fragment ions, and an SPPS synthesis-difficulty profile. It supports noncanonical residues and terminal modifications.