We have developed a spectrophotometric assay for the quantitative determination of feruloyl esterase activity based on release of 4-nitrophenol from a novel substrate, 4-nitrophenyl ferulate in an emulsion of Triton X-100 in aqueous buffer solution. The release of 4-nitrophenol was linear with reaction time at an early stage of the reaction with various esterase preparations. The method propose...

Programmed current chronopotentiometry, specifically current reversal and current decrease, is applied to electrode reactions characterized by a chemical reaction coupled between two charge-transfer reactions, the ECE mechanism. The equations for the transition times are derived and solved. Current-reversal results on systems following the ECE mechanism, p-nitrosophenol, p-nitrophenol, and o-ni...

1. The glucuronide conjugation of p-nitrophenol, phenolphthalein, o-aminophenol and 4-methylumbelliferone by rat liver microsomes has been studied. The detergent Triton X-100 activated UDP-glucuronyltransferase activity towards all these substrates, therefore the optimum activating concentration was added in all experiments. 2. Mg(2+) enhanced the conjugation of the substrates. 3. With phenolph...

Gunn rats, which have defects in bilirubin and 4-nitrophenol UDP-glucuronyltransferases (GT), were crossed with LA Wistar rats with a defect in androsterone GT. The F1 hybrids showed normal GT activities towards androsterone, bilirubin and 4-nitrophenol, demonstrating that Gunn and LA ('low activity') Wistar rats inherit a homozygous dominant trait for androsterone GT and bilirubin GT respectiv...

This work reports a comparative electrochemical behaviour study and p-nitrophenol analytical detection using silver solid amalgam, hanging dropping mercury, and silver electrodes. For this, square wave voltammetry was employed, where the analytical responses and the redox mechanisms could be compared for reduction processes of 4-nitrophenol by analysis of the voltammetric responses. The analyti...

A novel, magnetically separable composite photocatalyst, titania coated with magnetic activated carbon, is prepared by depositing TiO2 onto the surface of magnetic activated carbon which was prepared by directly adsorbing of magnetic Fe2O3 nanoparticles onto activated carbon. The samples are characterized by X-ray diffraction, scanning electron microscopy and vibration sample magnetometer. Spec...

Herbicides, Photosynthesis, Diphenylether, Inhibitors, Plastoquinone Several substituted diphenylethers were found to be effective inhibitors of photosynthetic electron flow in isolated thylakoid membranes from spinach chloroplasts. Their site of inhibition was localized with artificial acceptor and donor systems. The phenylether of an alkyl substituted nitrophenol is primarely inhibiting elect...

Pseudomonas putida B2 is able to grow on o-nitrophenol (ONP) as the sole source of carbon and nitrogen. ONP was converted by a nitrophenol oxygenase to nitrite and catechol. Catechol was then attacked by a catechol 1,2-dioxygenase and further degraded through an ortho-cleavage pathway. ONP derivatives which were para-substituted with a methyl-, chloro-, carboxy-, formyl- or nitro-group failed t...

We report the use of second harmonic generation (SHG) to study kinetics of adsorption of p-nitrophenol at the air/water interface of a flowing jet. Measurements of the SH signal strength and the polarization of the SH light at various distances (times) along the jet axis yield information about the development of the population density and orientation of nitrophenol at the air/ water interface....