The kinetic mechanism of the reaction of D-amino acid oxidase (EC 1.4.3.3) from Trigonopsis variabilis with [alpha-1H]- and [alpha-2H]phenylglycine has been determined. The pH dependence of Vmax is compatible with pKa values of approximately 8.1 and >9.5, the former of which is attributed to a base which should be deprotonated for efficient catalysis. The deuterium isotope effect on turnover is...

The mechanism of phosphatidylinositol-specific phospholipase C (PI-PLC) has been suggested to resemble that of ribonuclease A. The goal of this work is to rigorously evaluate the mechanism of PI-PLC from Bacillus thuringiensis by examining the functional and structural roles of His-32 and His-82, along with the two nearby residues Asp-274 and Asp-33 (which form a hydrogen bond with His-32 and H...

Synthesis and overexpression of a gene encoding Escherichia coli UDP-galactose 4-epimerase and engineered to facilitate cassette mutagenesis are described. General acid-base catalysis at the active site of this epimerase has been studied by kinetic and spectroscopic analysis of the wild-type enzyme and its specifically mutated forms Y149F, S124A, S124V, and S124T. The X-ray crystal structure of...

in this work, the efficiency, generality and applicability of new bronsted acidic ionic liquid (bail) 1-methyl-3-(2-(sulfooxy)ethyl)-1h-imidazol-3-ium chloride {[msei]cl} as heterogeneous and green catalyst for organic transformations are studied. herein, the following one-pot multi-component reactions in the presence of [msei]cl are investigated: (i) the synthesis of quinoxaline derivatives fr...

In this work, the efficiency, generality and applicability of new Bronsted acidic ionic liquid (BAIL) 1-methyl-3-(2-(sulfooxy)ethyl)-1H-imidazol-3-ium chloride {[Msei]Cl} as heterogeneous and green catalyst for organic transformations are studied. Herein, the following one-pot multi-component reactions in the presence of [Msei]Cl are investigated: (i) the synthesis of quinoxaline derivatives fr...

The depolymerization of natural biomass-based lignin is a definitive challenge, as it involves the integral breakdown complex and well-constructed structures. A sustainable method called ‘ionoSolv pretreatment’ employs ionic liquids in biomass processing. In this study, Bronsted acidic IL (BAIL); 1-methyl-3-(3-sulfopropyl)-imidazolium chloride, [C3SO3HMIM]Cl was synthesized commendably used to ...

Over the past two decades, polyoxometalates (POM) have received considerable attention as solid catalysts, due to their unique physicochemical characteristics, since, first, they very strong Bronsted acidity, approaching region of a superacid, and second, are efficient oxidizers that exhibit rapid redox transformations under fairly mild conditions. Their structural mobility is also highlighted,...