Search results for " SPECT"
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Profiling Dopamine-Induced Oxidized Proteoforms of β-synuclein by Top-Down Mass Spectrometry
2021
The formation of multiple proteoforms by post-translational modifications (PTMs) enables a single protein to acquire distinct functional roles in its biological context. Oxidation of methionine residues (Met) is a common PTM, involved in physiological (e.g., signaling) and pathological (e.g., oxidative stress) states. This PTM typically maps at multiple protein sites, generating a heterogeneous population of proteoforms with specific biophysical and biochemical properties. The identification and quantitation of the variety of oxidized proteoforms originated under a given condition is required to assess the exact molecular nature of the species responsible for the process under investigation…
Conformational investigation of alpha,beta-dehydropeptides. IX. N-Acetyl-(E)-alpha,beta-methylamide: stereoelectronic properties from infrared and th…
1998
The Fourier transform infrared spectra of Ac-(E)-deltaAbu-NHMe were analyzed to determine the predominant solution conformation(s) of this (E)-alpha,beta-dehydropeptide-related compound and the electron density perturbation in its amide groups. The measurements were performed in dichloromethane and acetonitrile in the region of mode vs (N-H), amide I, amide II and vs (C(alpha)=Cbeta). The equilibrium geometrical parameters, calculated by a method based on the density functional theory with the B3LYP functional and the 6-31G* basis set, were used to support spectroscopic interpretation and gain some deeper insight into the molecule. The experimental and theoretical data were compared with th…
Characterization and antimicrobial activity of the volatile components of the flowers of Magydaris tomentosa (Desf.) DC. collected in Sicily and Alge…
2014
The essential oils of the flowers of Magydaris tomentosa (Desf.) DC. (Apiaceae) collected in Sicily (MSi) and Algeria (MAl), respectively, were obtained by hydrodistillation, and their compositions were analysed. The analyses allowed the identification and quantification of 23 components in MSi and 60 compounds in MAl, respectively, showing a very different profile in the composition of the two populations. The main components of MSi were cembrene (28.2%), α-springene (17.5%) and β-springene (14.8%), also present in MAl but in lesser amount (0.4%, 1.8% and 0.9%, respectively), whereas the principal constituents of MAl were (E)-nerolidol (35.4%), α-costol (13.3%) and β-costol (6.8%). Both MS…
The Use of Stable Isotope Ratio Analysis to Trace European Sea Bass (D. labrax) Originating from Different Farming Systems
2020
This study aimed to determine whether isotopic ratio mass spectrometry (IRMS) can discriminate farmed European sea bass according to different farming systems and geographic origins. Dicentrarchus labrax of commercial size from three different rearing systems (concrete tank inland, sea cages, and extensive methods in valleys or salt works) were collected at the trading period (autumn&ndash