Objective: The aim of this study was to determinate chemical structure and mass weight of a product suspected as ε- poly- l- lysine from a Stretomyces strain.Methods: The chemical composition of the product was determined by thin layer chromatography( TLC); the UV- VIS wavelength scanning was used to analyze organic groups; the chemical bond among l- lysine residues was analyzed by heteronuclear multiple- bond correlation spectrum( HMBC).Tricine- SDS- PAGE was employed for the analysis of molecular weight.R...