When proteins are cleaved by various reagents into smaller peptides: the sequences produced by the various reagents will overlap allowing the discernment of the overall protein sequence. Most amino acids in the smaller peptides are altered to different chemical forms. The set of peptides produced by one reagent are separated from one another by SDS-PAGE. All the reagents are mixed with one protein sample and allowed to work simultaneously. The protein is divided into samples, and reagents are individually added to separate samples.