Certain acyl transfer and hydrolytic reactions catalyzed by chymotrypsin and related enzymes proceed with the formation of an isolable enzyme-substrate intermediate, in which the acyl portion of the substrate is covalently bound to the enzyme. A considerable body of evidence now exists which suggests that the site of enzyme acylation, as well as phosphorylat,ion, is the hydroxyl group of a seri...

The reaction between hydroxyl amine and Waugh-type polyoxometalate, enneamolybdomanganate(ΙV), was investigated under pseudo-first-order condition in aqueous perchloric acid. The product of the reaction was nitrous oxide as determined by studying the stoichiometry which requires one mol of oxidant per mole of hydroxylamine. The rate of reaction increases as hydrogen ion and oxidant, enneamolybd...

One heat-modifiable protein of Escherichia coli outer membrane does not completely change to the high-temperature form in the presence of magnesium ion in sodium dodecyl sulfate solution. When the metal ion complexing reagents ethylenediaminetetraacetic acid, phosphate ion, hydroxyl ion, or the competitive cations Zn2+ or Ca2+ are added to the sodium dodecyl sulfate-solubilized sample of outer ...

introduction: ca(oh) 2 -containing/forming materials are conventionally used for indirect pulp-capping and are theoretically able to release ca 2+ and oh - ions for hydrolytic dissociation. however, no evidence exists for ion diffusion through the remaining coronal dentin. the aim of this study was to design an innovative experimental set-up to test the ability of ca(oh) 2 -containing and ca(oh...

Hydrolytic lignin is a large-tonnage waste product of ethyl alcohol production and renewable resource. The structure characterized by the presence large number hydroxyl groups, which provides value as raw material for synthesis in polymer chemistry. But due to their low chemical stability dilute alkalis, acids solvents, lignins are little use wide practical use. introduction additional function...

The shikimate pathway of bacteria, fungi, and plants generates chorismate, which is drawn into biosynthetic pathways that form aromatic amino acids and other important metabolites, including folates, menaquinone, and siderophores. Many of the pathways initiated at this branch point transform chorismate using an MST enzyme. The MST enzymes (menaquinone, siderophore, and tryptophan biosynthetic e...

20(S)-Protopanaxadiol (PPD, 1) is one of the aglycones of the ginsenosides and has a wide range of pharmacological activities. At present, PPD has progressed to early clinical trials as an antidepressant. In this study, its fate in mixed human liver microsomes (HLMs) and human hepatocytes was examined for the first time. By using liquid chromatography-electrospray ionization ion trap mass spect...

For the past 40 years, the Moon has been described as nearly devoid of indigenous water; however, evidence for water both on the lunar surface and within the lunar interior have recently emerged, calling into question this long-standing lunar dogma. In the present study, hydroxyl (as well as fluoride and chloride) was analyzed by secondary ion mass spectrometry in apatite [Ca(5)(PO(4))(3)(F,Cl,...

OBJECTIVES This study was conducted to investigate the antioxidant potential of methanol extract and its derived fractions (hexane, ethyl acetate, butanol, and aqueous) of fruits of Monotheca buxifolia (Falc.) Dc., a locally used fruit in Pakistan. METHODS Dried powder of the fruit of M. buxifolia was extracted with methanol and the resultant was fractionated with solvents having escalating p...

Bifunctional human PAPS synthetase (PAPSS) catalyzes, in a two-step process, the formation of the activated sulfate carrier 3'-phosphoadenosine 5'-phosphosulfate (PAPS). The first reaction involves the formation of the 5'-adenosine phosphosulfate (APS) intermediate from ATP and inorganic sulfate. APS is then further phosphorylated on its 3'-hydroxyl group by an additional ATP molecule to genera...