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...

A novel detection method for organophosphate neurotoxins has been described, based on the fluorescence quenching of a Coumarin derivative. These dyes are similar in structure to some organophosphates (OPs), and they fluoresce in the blue-green region of the spectra. This methodology has been utilized for the detection of organophosphates whose hydrolysis product is p-nitrophenol by using an enz...

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...

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...

Fig. 3. Effect of inhibition of harmol sulphation by 2,6dichloro-4-nitrophenol ( D C N P ) on the excretion of harmol glucuronide (hg) and harmol sulphate (hs ) Harmol was infused at a rate of 0.76pmol/min after an intravenous loading dose of 4.8pmol. Bile and urine were collected as indicated by the mid-point of each collection period, and in each fraction harmol glucuronide and harmol sulphat...