1.Profiling histidine-containing dipeptides in rat tissues by liquid chromatography/electrospray ionization tandem mass spectrometry.
Aldini G1, Orioli M, Carini M, Maffei Facino R. J Mass Spectrom. 2004 Dec;39(12):1417-28.
The histidine-containing dipeptides carnosine (CAR) and structurally related anserine (ANS) and homocarnosine (HCAR), widely distributed in vertebrate organisms, have recently been proposed as endogenous quenchers for highly cytotoxic alpha,beta-unsaturated aldehydes generated by peroxidation. A sensitive, selective, specific and rapid liquid chromatographic/electrospray ionization tandem mass spectrometric assay was developed and validated for the simultaneous determination of these peptides in biological matrices in order to establish their plasma/tissue distribution. Samples (plasma or tissue homogenates from male rats) were prepared by protein precipitation with HClO(4) (1 : 1, v/v) containing H-Tyr-His-OH as internal standard. The supernatant was separated on a Phenomenex Sinergy polar-RP column with a mobile phase of water-acetonitrile-heptafluorobutyric acid (9 : 1 : 0.01, v/v/v) at a flow-rate of 0.2 ml min(-1), with a run time of 10 min.
2.[Synthesis of two median segments of human parathyrin (author's transl)].
Casaretto M, Danho W, Hesch RD, Zahn H. Hoppe Seylers Z Physiol Chem. 1982 Apr;363(4):407-23.
Human parathyrin-(32-43)-dodecapeptide (H-His-Asn-Phe-Val-Ala-Leu-Gly-Ala-Pro-Leu-Ala-Pro-OH) and tyrosyl-[human parathyrin-(43-55)-tridecapeptide] (H-Tyr-Pro-Arg-Asp-Ala-Gly-Ser-Gln-Arg-Pro-Arg-Lys-Lys-Glu-OH) were prepared, using the strategy of segment condensation in combination with acid-labile protecting groups. The peptides will be utilized for radioimmunoassay and receptor-binding studies.
3.HNE Michael adducts to histidine and histidine-containing peptides as biomarkers of lipid-derived carbonyl stress in urines: LC-MS/MS profiling in Zucker obese rats.
Orioli M1, Aldini G, Benfatto MC, Facino RM, Carini M. Anal Chem. 2007 Dec 1;79(23):9174-84. Epub 2007 Nov 3.
A new liquid chromatography-tandem mass spectrometric (LC-MS/MS) approach, based on the precursor ion scanning technique using a triple-stage quadrupole, has been developed to detect free and protein-bound histidine (His) residues modified by reactive carbonyl species (RCS) generated by lipid peroxidation. This approach has been applied to urines from Zucker obese rats, a nondiabetic animal model characterized by obesity and hyperlipidemia, where RCS formation plays a key role in the development of renal and cardiac dysfunction. The immonium ion of His at m/z 110 was used as a specific product ion of His-containing peptides to generate precursor ion spectra, followed by MS2 acquisitions of each precursor ion of interest for structural characterization. By this approach, three novel adducts, which are excreted in free form only, have been identified, two of them originating from the conjugation of 4-hydroxy-trans-2-nonenal (HNE) to His, followed by reduction/oxidation of the aldehyde: His-1,4-dihydroxynonane (His-DHN), His-4-hydroxynonanoic acid (His-HNA), and carnosine-HNE, this last recognized in previous in vitro studies as a new potential biomarker of carbonyl stress.
4.Preparations of Boc-Cys(S-Pyr)-OH and Z-Cys(S-Pyr)-OH and their applications in orthogonal coupling of unprotected peptide segments.
Huang H1, Carey RI. J Pept Res. 1998 Apr;51(4):290-6.
Boc-Cys(S-Pyr)-OH and Z-Cys(S-Pyr)-OH were prepared by addition of their cysteine derivatives to 3 equiv of 2,2'-dipyridyldisulfide in one portion. 2-Mercaptopyridine was removed by addition of 0.1 M Cu(NO3)2 to the solution. Both derivatives are white solids and can be used to facilitate the formations of heterodisulfide bonds. Two methods of synthesizing peptides with N-terminal Cys(S-Pyr) were also provided. Two peptide thiocarboxylic acids H-Tyr-Ser-Ala-Glu-Leu-Val-SH and H-Tyr-Ser-Ala-Glu-Leu-Gly-SH were prepared on the thioester benzhydryl resin with the cleavage condition of 1.0 M TFMSA/TFA instead of HF. From the orthogonal couplings of these peptides with H-Cys(S-Pyr)-Tyr-Ser-Glu-Leu-Ala-NH2, both intramolecular acyl transfers finished at pH 7 at about 15 to 20 min. The intermediate acyl disulfide peptide was collected by high-performance liquid chromatography and identified by liquid chromatography-mass spectrometry.
