As an analytical method used to characterize the primary structure of proteins especially obtained through recombinant DNA technology, peptide mapping involves the chemical or enzymatic digestion of a protein to selectively cleave amide bonds between amino acid residues to yield a predictable set of peptides. At Creative Proteomics, the samples are prepared in a way to minimize artificially induced variations. With combination of different enzymes, higher coverage, even 100% coverage sometimes is obtained.