Topic
Molecular weight, composition and notation for amino-acid sequences.
Average and monoisotopic molecular weight plus molecular formula for any peptide sequence, with terminal modifications and disulfide bonds.
Composition, net charge at any pH, isoelectric point, GRAVY hydropathy and extinction coefficient for a peptide sequence.
Count residues and peptide bonds, and convert a sequence between one-letter and three-letter amino-acid codes.
Why a peptide weighs less than its amino acids added together, how residue masses work, when to use average or monoisotopic mass, and how terminal groups and disulfides change the result.
What the sequence analyzer reports and how to read it: net charge at a given pH, isoelectric point, GRAVY hydropathy and the extinction coefficient at 280 nm, with the limits of each estimate.
How peptide sequences are written: direction from N- to C-terminus, the 20 one- and three-letter codes, terminal groups like H- and -NH2, and the ambiguous codes that trip up calculators.