title: Quantitative analysis of methionine enkephalin and beta-endorphin in the pituitary by liquid secondary ion mass spectrometry and tandem mass spectrometry.
abstract: This manuscript reviews the use of an off-line combination of liquid chromatography (LC) and mass spectrometry (MS) to quantify endogenous neuropeptides in biological tissues and fluids, and tandem MS (MS/MS) to optimize the molecular specificity of the quantification of native peptides. Reversed-phase high-performance liquid chromatography (RP-HPLC) was used to purify selected endogenous neuropeptides from biological tissues and fluids. Liquid secondary ion MS (LSI-MS), also known as fast atom bombardment (FAB), is used to desorb and to ionize the peptide. The corresponding stable isotope-incorporated synthetic peptide of each peptide is used as the internal standard (I.S.) for quantification. The measurement of methionine enkephalin (ME) and of beta-endorphin1-31 (BE) in the human pituitary is described. This analytical method offers the highest molecular specificity for the measurement of a fully post-translationally modified peptide.
authors.affiliation: Department of Biochemistry, University of Tennessee, Memphis 38163, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Desiderio
authors.forename: X
authors.initials: X
authors.lastname: Zhu
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004744:Enkephalin, Methionine / Q000032:analysis*; D006801:Humans; D013058:Mass Spectrometry; D010902:Pituitary Gland / Q000737:chemistry*; D001615:beta-Endorphin / Q000032:analysis*
chemical_list: D004744:Enkephalin, Methionine; D001615:beta-Endorphin