An algorithm to analyse the hydrolysis pathway of peptides and proteins by sequence analyses of unfractionated digestion mixtures

We have designed and implemented on a personal computer a program for identifying and quantifying the fragments present in a peptide mixture obtained by hydrolysing a polypeptide of known sequence using digesting agents. The qualitative data utilized by the main algorithm consist of the target sequence of the intact molecule and the amino acid residues identified at each step of the automatic sequence analysis of the unfractionated digestion mixture. In this way, the sequence of each fragment present in the mixture is quickly reconstructed. Furthermore, if the quantitative data of the amino acid residues identified at each step of the sequence analysis are utilized, the program will correlate the sequence of each fragment to its amount. We furnish an example of the application intended for the rapid identification and characterization of the extracellular proteinases produced by a basidiomycete fungus, utilizing the bovine insulin beta-chain as target substrate. A variety of uses for the method are discussed.