A standard assay for measuring alkaline phosphatase activity is detecting the production of nitrophenol from the artificial substrate p-nitrophenol phosphate. Nitrophenol absorbs light at 420 nm, which provides a convenient detection method. However, the absorbance of nitrophenol varies with pH. This variation complicates the use of the colorimetric assay to study the pH-dependence of alkaline ...

The relationship between alveolar PO2 and the rate of O-demethylation of p-nitroanisole, a model substrate for cytochrome P-450 -linked mixed-function oxidation, was evaluated in the isolated rabbit lung perfused with Krebs-Ringer bicarbonate buffer. The appearance of the product, p-nitrophenol, in the pulmonary perfusate was measured spectrophotometrically, The PO2 of the ventilating gas was v...

The inner surface of a metallic tube (i.d. 0.5 mm) was coated with a palladium (Pd)-based thin metallic layer by flow electroless plating. Simultaneous plating of Pd and silver (Ag) from their electroless-plating solution produced a mixed distributed bimetallic layer. Preferential acid leaching of Ag from the Pd-Ag layer produced a porous Pd surface. Hydrogenation of p-nitrophenol was examined ...

The npd gene cluster, which encodes the enzymes of a p-nitrophenol catabolic pathway from Arthrobacter sp. strain JS443, was cloned and sequenced. Three genes, npdB, npdA1, and npdA2, were independently expressed in Escherichia coli in order to confirm the identities of their gene products. NpdA2 is a p-nitrophenol monooxygenase belonging to the two-component flavin-diffusible monooxygenase fam...

A Sb/palygorskite (PAL) composite was synthesized by a facile solvothermal process and applied in catalytic hydrogenation of p-nitrophenol for the first time. It was found that the Sb nanoparticles with the sizes of 2-5 nm were well dispersed on the fiber of PAL, while partial aggregated Sb nanoparticles with sizes smaller than 200 nm were also loaded on the PAL. The Sb/PAL composite with 9.7% ...

Bioelectrochemical system (BES) for recalcitrant p-nitrophenol (PNP) removal was investigated in this study. Effective removal of PNP at rates up to 9.14 ± 0.48 mol m(-3)d(-1) was achieved at an energy consumption as low as 0.010 ± 0.002 kWh mol(-1) PNP. PNP removal rate was enhanced with negative cathode potential, increased influent PNP concentration and shortened hydraulic retention time (HR...

Nitrophenol is one of the most highly toxic heavy pollutants in environment. It has a slow degradation rate, and harmful to humans even at low concentrations. Therefore, it crucial detect nitrophenol quickly, easily, accurately. In this study, isomers (o-nitrophenol, m-nitrophenol, p-nitrophenol), solid liquid phases with methanol or acetone as solvent, were investigated using Raman spectroscop...

The dissociation constants of the following substituted phenols in 50 wt percent methanol have been measured at 25 °C: o-nitrophenol, p-nitrophenol, 4-methyl-2-nitrophenol, 2,6-di chlorophenol , pentachlorophenol. The respective values found, expressed as pK values, are 7.91" 7.692 , 8.28" 7.680 , and 5.27.. The dissociation cons tants of 4-methyl-2-nitrophenol and pentachlorophenol, again exp ...

Abstract p -Nitrophenol (PNP) is an important environmental pollutant and can causes significant health risks. Compared with the traditional methods, biodegradation a useful one to completely remove harmful pollutants from environment. Here, engineered strain was first constructed by introducing PNP pathway via hydroquinone (HQ) into Escherichia coli . In BL-PNP, degraded β-ketoadipate subseque...

A mixed microbial culture was adapted to growth on parathion to determine the feasibility of using microorganisms to detoxify concentrated parathion in agricultural wastes. In a 600-ml chemostat, the culture was able to degrade 50 mg of parathion per liter per h. Para-nitrophenol, produced by enzymatic hydrolysis of parathion, caused delays in exponential growth which were directly proportional...