A combined experimental and theoretical approach has been employed to establish the basicity and proton affinity of SiF4 and the structure of SiF4H . The kinetics and energetics for the transfer of a proton between SiF4, N2, and Xe have been explored experimentally in helium at 0.35 6 0.02 torr and 297 6 3 K with a selected-ion flow tube apparatus. The results of equilibrium constant measuremen...

Proton Pumping in Cotychrome c Oxidase by Jianxun Lu Advisor: Professor Marilyn Gunner Cytochrome c oxidase (CcO) is a large trans-membrane protein, which is the final enzyme in the respiratory electron transport chain in mitochondria or aerobic bacteria. It implements proton pumping through the mitochondrial membrane against the electrochemical gradient, by utilizing the chemical energy releas...

Ion-molecule reactions of Me2S2 with a wide range of aliphatic carbanions differing by structure and proton affinity values have been studied in the gas phase using mass spectrometry techniques and DFT calculations. The analysis of the spectra shows a variety of product ions formed via different reaction mechanisms, depending on the structure and proton affinity of the carbanion. Product ions o...

The gas-phase acidity and proton affinity of thymine, cytosine, and 1-methyl cytosine have been examined using both theoretical (B3LYP/6-31+G*) and experimental (bracketing, Cooks kinetic) methods. This paper represents a comprehensive examination of multiple acidic sites of thymine and cytosine and of the acidity and proton affinity of thymine, cytosine, and 1-methyl cytosine. Thymine exists a...

Listeria monocytogenes transported glucose by a high-affinity phosphoenolpyruvate-dependent phosphotransferase system and a low-affinity proton motive force-mediated system. The low-affinity system (Km = 2.9 mM) was inhibited by 2-deoxyglucose and 6-deoxyglucose, whereas the high-affinity system (Km = 0.11 mM) was inhibited by 2-deoxyglucose and mannose but not 6-deoxyglucose. Cells and vesicle...

The prospect that protons from water may be transferred to N-heterocyclic molecules due to the presence of an excess electron is studied in hydrated azabenzene cluster anions using anion photoelectron spectroscopy and computational chemistry. In the case of s-triazine (C3H3N3), which has a positive adiabatic electron affinity, proton transfer is not energetically favored nor observed experiment...

The reaction mechanisms by which antioxidants can exert their activity are: hydrogen atom transfer (HAT), proton coupled electron transfer (PCET), sequential proton loss electron transfer (SPLET), single electron transfer proton transfer (SET-PT), radical adduct formation, and sequential proton loss hydrogen atom transfer. The antioxidative activity of different compounds (flavones, flavonols, ...

Je re T. K oskinen Molecular Physics Laboratory. Department of Physics, POB 9, FIN-00014 University of Helsinki, Finland Z. Naturforsch. 53b, 386-392 (1998); received November 21, 1997 Proton Affinity, Gas Phase Basicity, Acid Dissociation Constant The structures of glyoxal bis(amidinohydrazone) (GBG) free base and glyoxal bis(amidinohydrazonium) monocation and dication were calculated quantum ...

The glycosidic bond torsion angles and the conformations of the ribose of MgZCATP, Mg2+ADP and Mg2+AdoPP[NH]P (magnesium adenosine 5'[/?,pimido] triphosphate) bound to Ca2+ATPase, both native and modified with fluorescein isothiocyanate (FITC), in intact sarcoplasmic reticulum have been determined by the measurement of proton-proton transferred nuclear Overhauser enhancements by 'H-NMR spectros...