منابع مشابه
Determination of the gas-phase acidities of oligopeptides.
Amino acid residues located at different positions in folded proteins often exhibit different degrees of acidities. For example, a cysteine residue located at or near the N-terminus of a helix is often more acidic than that at or near the C-terminus (1-6). Although extensive experimental studies on the acid-base properties of peptides have been carried out in the condensed phase, in particular ...
متن کاملEstimation of Gas Phase Acidities of Glucose, Galactose, Mannose and Talose by the Kinetic Method
Carbohydrates are the most abundant biomolecules found in the nature. Monosaccharides, such as glucose, galactose and fructose are the basic carbohydrate units and they bind together by different types of glycosidic linkages to form different types of polysaccharides. Monosaccharides bind with nucleobases, i.e. with purines and pyrimidines, to give nucleosides and subsequently nucleotides (DNA ...
متن کاملStructural and Solvent Effects Evaluated from Acidities Measured in Dimethyl Sulfoxide and in the Gas Phase’
with the experimental log kobsd values. Application of the test to reactions with Ph2CHCl, which gives S N ~ kinetics and products with no evidence of radical-type products, gave linear Marcus-type plots and log ksET values corresponding to the experimental log kobsd values. It was concluded that the “SN2 reactions” of 9-R2N-Flions with Ph2CHCl are occurring by a radical pair mechanism. This ap...
متن کاملA comparison of the gas phase acidities of phospholipid headgroups: experimental and computational studies.
Proton-bound dimers consisting of two glycerophospholipids with different headgroups were prepared using negative ion electrospray ionization and dissociated in a triple quadrupole mass spectrometer. Analysis of the tandem mass spectra of the dimers using the kinetic method provides, for the first time, an order of acidity for the phospholipid classes in the gas phase of PE < PA << PG < PS < PI...
متن کاملDetermination of the gas-phase acidities of cysteine-polyalanine peptides using the extended kinetic method.
We determined the gas-phase acidities of two cysteine-polyalanine peptides, HSCA3 and HSCA4, using a triple-quadrupole mass spectrometer through application of the extended kinetic method with full entropy analysis. Five halogenated carboxylic acids were used as the reference acids. The negatively charged proton-bound dimers of the deprotonated peptides with the conjugate bases of the reference...
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ژورنال
عنوان ژورنال: Journal of the American Society for Mass Spectrometry
سال: 1993
ISSN: 1044-0305,1879-1123
DOI: 10.1016/1044-0305(93)80051-y