the studies performed about electrochemical oxidation 2-amino-4-methylphenol indicate that ortho-quinone yielded through oxidation of this chemical compound was unstable and it could be used as michael acceptor under solvent influences, carrier electrolyte, additives and could be transformed into the various compounds in the form of 1-4 addition michael reaction. based on this, in the paper fir...

The ?-effect is a term used to explain the dramatically enhanced reactivity of ?-nucleophiles (R?Y?X:?) compared their parent normal nucleophile (R?X:?) by deviating from classical Brønsted-type reactivity-basicity relationship. exact origin this effect is, however, still heavily under debate. In work, we have quantum chemically analyzed set anionic nucleophiles, including O-, N- and S-based ?-...

Self-splicing group I introns use guanosine as a nucleophile to cleave the 5' splice site. The guanosine-binding site has been localized to the G264-C311 base pair of the Tetrahymena intron on the basis of analysis of mutations that change the specificity of the nucleophile from G (guanosine) to 2AP (2-aminopurine ribonucleoside) (F. Michel et al. (1989) Nature 342, 391-395). We studied the eff...

Wine oxidation is mediated by the redox cycling of iron between two states: iron(II) oxygen and reduction iron(III) phenols. The effects phenolic structure, pH, copper on rates these reactions were evaluated in model wine. In absence a nucleophile, pyrogallol exhibited greater reactivity with than 4-methylcatechol. However, both compounds ultimately required aid from nucleophile benzenesulfinic...

γ-Glutamyltranspeptidases (γ-GTs), ubiquitous in glutathione metabolism for γ-glutamyl transfer/hydrolysis, are N-terminal nucleophile (Ntn)-hydrolase fold proteins that share an autoproteolytic process for self-activation. γ-GT homologues are widely present in Gram-positive actinobacteria where their Ntn-hydrolase activities, however, are not involved in glutathione metabolism. Herein, we demo...

BACKGROUND Vibrio harveyi GH20 β-N-acetylglucosaminidase (VhGlcNAcase) is a chitinolytic enzyme responsible for the successive degradation of chitin fragments to GlcNAc monomers, activating the onset of the chitin catabolic cascade in marine Vibrios. METHODS Two invariant acidic pairs (Asp303-Asp304 and Asp437-Glu438) of VhGlcNAcase were mutated using a site-directed mutagenesis strategy. The...