1,721,204 research outputs found
HPLC and MS analysis for the identification and characterisation of peptides presented in the context of the non-classical human leukocytes antigen (HLA) class I molecule HLA-E.
No full textSynthesis of 1H-Pyrazino[1,2-a]pyrido[2,3-e]pyrazine and 2H-Pyrano[2,3-b]pyrido[2,3-e]pyrazine Derivative.
No full textTop-down proteomics with a quadrupole time-of-flight mass spectrometer and collision-induced dissociation.
No full textAchievements and perspectives of top-down proteomics
No full textOver the last years, top-down (TD) MS has gained a remarkable space in proteomics, rapidly trespassing the limit between a promising approach and a solid, established technique. Several research groups worldwide have implemented TD analysis in their routine work on proteomics, deriving structural information on proteins with the level of accuracy that is impossible to achieve with classical bottom-up approaches. Complete maps of PTMs and assessment of single aminoacid polymorphisms are only a few of the results that can be obtained with this technique. Despite some existing technical and economical limitations, TD analysis is at present the most powerful instrument for MS-based proteomics and its implementation in routine workflow is a rapidly approaching turning point in proteomics. In this review article, the state-of-the-art of TD approach is described along with its major advantages and drawbacks and the most recent trends in TD analysis are discussed. References for all the covered topics are reported in the text, with the aim to support both newcomers and mass spectrometrists already introduced to TD proteomics
How to Discriminate Between Leucine and Isoleucine by Low Energy ESI-TRAP MSn
No full textIn peptide sequencing experiments involving a single step tandem mass acquisition, leucine and isoleucine are indistinguishable because both are characterized by a 113 Da mass difference from the other peptide fragments in the MS2 spectrum. In this work, we propose a new method to distinguish between these two amino acids in consecutive MSn experiments, exploiting a gas-phase fragmentation of isoleucine that leads to a diagnostic 69 Da ion. We used this method to assess the Leu/Ile residues of several synthetic peptides. The procedure was then tested on a tryptic digest of myoglobin, assigning the correct amino acid in the majority of the peptides. This work was performed with an old and low-resolution instrument, thus demonstrating that our method is suitable for a wide number of ion trap mass spectrometers, not necessarily expensive or up-to-date
Simple synthesis of P1P2-Diadenosine 5'-pyrophosphate
No full textPyrophosphate-linked coenzymes play essential roles in several biochemical systems. Symmetrical diadenosine-5'-pyrophosphate (Ap2A) has been synthesized from adenosine-5'-phosphate in virtually quantitative yield. The simple procedure is carried out in anhydrous pyridine using adenosine phosphoromorpholidate and adenosine monophosphate bis-(tri-n-butylammonium salt) as coupling reagents
Biochemical characterization of the plasma membrane Ca++-pumping ATP-ase activity present in the gill cells of Mytilus Galloprovincialis Lam.
No full textSynthesis, uptake and intracellular metabolism of a hydrophobic tetrapeptide-peptide nucleic acid (PNA)-biotin molecule
No full textCombining voltammetric and mass spectrometric data to evaluate iron organic speciation in subsurface coastal seawater samples of the Ross sea (Antarctica)
No full textIron (Fe) is the most important trace element in the ocean, as it is required by phytoplankton for photosynthesis and nitrate assimilation. Iron speciation is important to better understand the biogeochemical cycle and availability of this micronutrient, in particular in the Southern Ocean. Dissolved Fe (dFe) concentration and speciation were determined in 24 coastal subsurface seawater samples collected in the western Ross sea (Antarctica) during the austral summer 2017 as part of the CELEBeR (CDW Effects on glacial mElting and on Bulk of Fe in the Western Ross sea) project. ICP-DRC-MS was used for dFe determination, whereas CLE-AdSV was used to obtain the concentration of complexed and free dFe, of the ligands, and the values of the stability constants of the complexes. Dissolved Fe values ranged from 0.4 to 2.5 nM and conditional stability constant (logK'Fe'L) from 13.0 to 15.0, highlighting the presence of Fe-binding organic complexes of different stabilities. Principal component analysis (PCA) allowed us to point out that Terra Nova Bay and the neighboring area of Aviator and Mariner Glaciers were different in terms of chemical, physical, and biological parameters. A qualitative investigation on the nature of the organic ligands was carried out by HPLC-ESI-MS/MS. Results showed that siderophores represented a heterogeneous class of organic ligands pool
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