title: Quantification of [Dmt1]DALDA in ovine plasma by on-line liquid chromatography/quadrupole time-of-flight mass spectrometry.
abstract: The synthetic peptide [Dmt(1)]DALDA (Dmt-D-Arg-Phe-Lys-NH(2); Dmt = 2',6'-dimethyltyrosine; 'super-DALDA') is a mu opioid-receptor agonist. On-line liquid chromatography/quadrupole time-of-flight mass spectrometry and the corresponding stable isotope-incorporated synthetic peptide internal standard were used to quantify [Dmt(1)]DALDA that had been extracted from ovine plasma samples. The [M+2H](2+) ion was used to construct the calibration curve, and the product ion was used for verification of the peptide. The detection sensitivity for the [Dmt(1)]DALDA [M+2H](2+) ion was 12.5 fmol and 50 fmol for the m/z 432.3 product ion. The concentration profile of [Dmt(1)]DALDA was determined from a set of ovine plasma samples. The molecular specificity of the peptide quantification was confirmed by tandem mass spectrometry (MS/MS).
authors.affiliation: Charles B Stout Neuroscience Mass Spectrometry Laboratory, University of Tennessee Health Science Center, 847 Monroe Avenue, Memphis, TN 38163, USA.
authors.forename: Haibao
authors.initials: H
authors.lastname: Wan
authors.forename: Dominic M
authors.initials: DM
authors.lastname: Desiderio
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002138:Calibration; D002853:Chromatography, Liquid / Q000379:methods*; D004563:Electrochemistry; D007477:Ions; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D009842:Oligopeptides / Q000097:blood* / Q000138:chemical synthesis / Q000737:chemistry; D017450:Receptors, Opioid, mu / Q000819:agonists; D012015:Reference Standards; D012680:Sensitivity and Specificity; D012756:Sheep / Q000097:blood
chemical_list: D007477:Ions; D009842:Oligopeptides; D017450:Receptors, Opioid, mu; C063076:tyrosyl-arginyl-phenylalanyl-lysinamide