[Structure of a pepsin fragment containing the functionally important aspartic acid residue].

The structure of B-5 fragment obtained under degradation of pig pepsin by cyanogen bromide is determined. B-5 fragment is a central part of pepsin molecule and it contains 46 amino acids, including a functionally important aspartic residue of the active site of the enzyme. Amino acid sequence of B-5 fragment was established by means of sequenator analysis and of studying the structure of peptides isolated from B-5 fragments.