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Showing 1 to 9 of 9 for “"General acid/base"”.
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Computational studies of the self-cleavage mechanism in the glmS ribozyme
… phosphodiester bond at a certain position via a general acid-base mechanism. This work explored the following aspects of its self-cleavage mechanism: general acid-base species, multiple roles of the cofactor GlcN6P, as well as the beneficial and deleterious effects of metal ions. Computational …
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Toward the Synthesis of Nuclease Models.
… enzymes that can specifically recognize nucleic acids and hydrolyze their phosphodiester bonds effectively. As is the case with many hydrolases, nucleases often carry one or more metal centers. Cooperation between such metal centers and other interactions involving general acid-base activities …
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Synthesis of Phenothiazinium Derivatives
… ôhydrolase modelsö use molecular recognition based on ??? stacking between the phenothiazinium ring and aromatic rings of specific substrates, such as anthracene monophosphate, while imidazole groups catalyze the hydrolysis of the phosphate ester by general acid-base mechanism.</p>
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Kinetic studies of the mechanism of transimination
… to be a geminal-diamine. A Bronsted plot for general base catalysis of the reaction with 2,2,2- trifluoroethylamine is curved with limiting slopes of 1.0, for catalysts of low pK<sub>a</sub>, and 0.0, for catalysts of high pK<sub>a</sub>. The break occurred at the estimated pK<sub>a</sub> for …
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Investigation of ordered shell nanoparticles as catalytic platforms for organic synthesis
… structure, previous work has discovered a general, spontaneous ordering of long, aliphatic molecules on the surfaces of nanoparticles. This ordering generates stripe-like domains, termed ripple domains, which have widths less than a nanometer and well-defined spatial separations. This …
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Enzymatic Characterization of N-Acetyl-1-D-myo-inosityl-2-amino-2-deoxy-alpha-D-glucopyranoside Deacetylase (MshB)
… and oxidative conditions. MshB employs a general acid-base catalyst mechanism wherein the Asp15 functions as a general base to activate the metal-bound water nucleophile for attack of the carbonyl carbon on substrate. Proton-transfer from a general acid catalyst facilitates breakdown of …
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Enzymatic Ring Formation in Polyether Tetronate Antibiotic Biosynthesis
… conversion of T-22 into tetronasin were a general acid/ base or a pericyclic mechanism. Site-directed mutagenesis of the Tsn15 active site indicated that none of the acid/base amino acid side chains were essential for activity, favouring instead the pericyclic mechanism.
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Synthesis of Chemical Models of Hydrolase Enzymes for Intramolecular Catalysis.
<p>Most nuclease enzymes can hydrolyze phosphoester bonds (in DNA and RNA) by using metal ions cofactors that coordinate and activate water molecules in the enzymes' active sites. However, there are some hydrolase enzymes (including nucleases) that can function without the aid of metal ions. …
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Mechanism of Substrate Specificity and Catalysis in Retaining β-Glucosidases From Maize and Sorghum
… the substrate binding sites in Glu1 and Dhr1. Based on structural analysis of Glu1 and Dhr1, chimeric β-glucosidases (Glu1/Dhr1) were constructed by shuffling the C-terminal amino acids of Glu1 with the homologous region of Dhr1 to study the mechanism of substrate specificity. The resulting …