title: Chromatography of peptides related to beta-endorphin.
abstract: Chromatographic procedures are described here for the resolution of beta-endorphin and its related peptides at picomolar concentration. Initially gel filtration is carried out on Sephadex G75 in 50% acetic acid, providing peptides with the approximate molecular size of beta-endorphin. The group of beta-endorphin-related peptides is resolved by ion-exchange chromatography on the pyridinium form of sulfopropyl Sephadex C25 in the presence of 50% acetic acid. The addition of 125I-labeled marker peptides prior to chromatography allows the recovery of each peptide to be calculated and provides a guide for identifying the elution positions of the endogenous peptides. Additional resolution can be obtained by high-pressure liquid chromatography (HPLC) of the sulfoxide forms of the peptides on muBondapak C18 under acidic conditions. The advantages and disadvantages of ion-exchange chromatography and high-pressure liquid chromatography are discussed for the purification of small amounts of basic, hydrophobic peptides.
mesh_terms: D002850:Chromatography, Gel / Q000379:methods; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002852:Chromatography, Ion Exchange / Q000379:methods; D004723:Endorphins / Q000032:analysis*; D010455:Peptides / Q000032:analysis*; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D010455:Peptides; D001615:beta-Endorphin