Combination of Derivatization–HPLC–MS and Enzymatic Hydrolysis–Edman Degradation for Amino Acid Sequence and Configuration of Polymyxin B Components

An analysis strategy that can simultaneously determine the amino acid site information and configuration for polymyxin (PM) components is reported in this study. The main components of PMB1, PMB2, and PMB1-I (the Leucine at position 7 changed to be Isoleucine) were purified from the mixture of PMB. The PMB component was hydrolyzed by hydrochloric acid to be a mixture of amino acids, which were derivatized with Marfey’s reagent of...