A system and method for characterizing protein molecules. A protein molecule of interest is isolated from other types of protein molecules. The protein molecule of interest is modified to a one-dimensional structure from the natural three-dimensional structure of the protein molecule. Each of a first type of amino acid residue of the protein molecule is labeled with a first tag. Each of a second type of amino acid residue of the protein molecule is labeled with a second tag. The first and second tags impart to the protein molecule a detectable set of characteristic ancillary properties that facilitates distinction of the protein molecule of interest from other types of protein molecules. When these ancillary properties are detected, a fingerprint of the protein molecule is revealed. A listing of known protein molecules and of the fingerprints corresponding to each of the known protein molecules serves as a library to facilitate identification of unknown proteins. A fingerprint of a protein molecule of interest determined in the same manner as the fingerprints of known proteins listed in the library is compared with fingerprints of the known protein molecules to identify the protein molecule of interest.