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Synthesis And Characterization Of Bifunctional Silica Gel Surfaces, Alufelwi Maxwell Tshavhungwe
Synthesis And Characterization Of Bifunctional Silica Gel Surfaces, Alufelwi Maxwell Tshavhungwe
Masters Theses
Bifunctional silica surfaces consisting of various combinations of the following organofunctional silanes were synthesized and characterized using diffuse reflectance infrared spectroscopy: hexamethyldisilazane, octyldimethylmethoxysilane, phenyldimethylethoxysilane, (3-aminopropyl) -dimethylmethoxysilane, ( 2 - cyanoethyl)triethoxysilane, and trimethylmethoxysilane.
The relative amounts of organosilanes loaded on a silica surface were obtained from band area ratios of IR bands. Ratios of organosilanes bonded to the same silica surface were calculated from normalized band areas of the isolated silanol peak. In reactions in which surface coverage was incomplete, the relative amount of inaccessible silanols was determined from the band area ratio of the silanol peak. Comparisons of organosilane loading …
Mechanistic Studies On Malate Dehydrogenase From Escherichia Coli, S. Kirk Wright
Mechanistic Studies On Malate Dehydrogenase From Escherichia Coli, S. Kirk Wright
Masters Theses
Kinetic studies and chemical modification studies were performed on malate dehydrogenase from Escherichia coli (eMDH). Chemical modification studies using diethylpyrocarbonate and iodoacetic acid, along with log V/K profiles indicate that one ionizing group with a pKa between 7.9 and 8.5 acts as a general acid/base in the catalytic mechanism. Log V profiles suggest that malate binds to the correctly protonated form of the enzyme. These results imply that a histidine residue is required for catalysis.
A primary deuterium kinetic isotope effect of 1.43 (±0.14) was observed on V/K using malate-2-d, while no isotope effect was measured on Vmax …