Resonance Raman spectroscopic studies unequivocally indicate that the absorption band at about 500 nm, observed when 2-(4′hydroxyphenylazo)-benzoic acid (HABA) interacts with either avidin or bovine serum albumin in neutral aqueous solution, originates from the protein-bound hydrazone form of t...

The resonance Raman spectrum of 2-(4′-hydroxyphenylazo)-benzoic acid (HABA) is pH dependent; the spectral changes are related to the formation of protonated and deprotonated ionic species of the dye molecule. In addition a tautomeric equilibrium process between azo and hydrazone forms of HABA i...

A novel matrix substance, 2-(4-hydroxyphenylazo)benzoic acid, or HABA, has been found to be very advantageous for matrix-assisted ultraviolet laser desorption ionization mass spectrometry. This compound has been successfully used for the desorption of peptides, proteins, and glycoproteins up to ...

The mechanism of the binding of 2-(4′-hydroxyphenylazo)benzoic acid (HABA) to bovine serum albumin was studied by relaxation methods as well as the binding isotherm using gel chromatography. A single relaxation was observed over a wide range of HABA concentration except at the extremes of high ...

Resonance Raman spectra of 2-(4′-hydroxyphenylazo)-benzoic acid have been recorded for aqueous and ethanolic solutions. The change of pH of the aqueous solution gives four types of spectra corresponding to the stages of protonation and deprotonation processes. On addition of bovine serum albumi...

The binding and thermodynamic parameters of the two binding forms of 2-(4′-hydroxyphenylazo)benzoic acid to bovine serum albumin were estimated. The number of the binding sites of the azo form was 3.2 and that of the hydrazone form was 0.7. The binding of the hydrazone form was affected only by...

2-(4-Hydroxyphenylazo)benzoic acid (1) and 3,5-dimethoxy-4-hydroxycinnamic acid (2) (also known as sinapinic acid), two matrices for the research of matrix-assisted laser desorption/ionization time-of-flight mass spectrum (MALDI-TOF-MS), have been structurally elucidated in this paper. The forme...

The optimized geometrical structure, vibrational and electronic transitions, chemical shifts and nonlinear optical properties of 2-(4-hydroxyphenylazo)benzoic acid (HABA) compound were presented in this study. The ground state geometrical structure and vibrational wavenumbers were carried out by...

In our previous work we showed that malaoxon, the first and main metabolite of the commonly used organophosphorus insecticide malathion, unlike its parent compound, damaged DNA in human lymphocytes. To search for the mechanism(s) underlying the observed effect we investigated the action of malao...

The synergistic effect of triphenyl phosphate (a carboxyesterase inhibitor), sesamex (inhibitor of microsomal oxidation) and O,O-diethyl O-phenyl phosphorothioate on the toxicity of malathion and malaoxon for one susceptible and two resistant strains of housefly was studies. It was found that in...

Interspecies comparisons indicate that fish are relatively more resistant to acute intoxication with parathion and paraoxon than are rodents. In contrast, fish are more sensitive to malathion and malaoxon. The following investigation was designed to determine if species-related differences in th...

The basis of malathion resistance was examined by comparisons of susceptible and resistant strains of Drosophila melanogaster. Increased levels of mixed-function oxidase (MFO) activity were highly correlated (r = +0.95, P

Malaoxon, the first and main metabolite of malathion, unlike its parent compound, can damage DNA in human lymphocytes, by mechanism(s) including oxidative action. Vitamin C may inhibit the DNA-damaging effect of malaoxon. To explore this effect further, we investigated the action of malaoxon on ...

Malathion and its oxygen analogue, malaoxon, are carcinogenic in Osborne-Mendel and Fischer-344 rats. Benign and malignant neoplasms at all sites were increased in Osborne-Mendel and Fischer-344 male and female rats ingesting malathion. Both Osborne-Mendel and Fischer-344 male rats were more sus...

The inhibition of lysyl hydroxylation in newly synthesized collagen by malathion and its oxidation product malaoxon were studied with cultured rat fetal lung fibroblasts. Exposure of these cells to 125 μM malathion or malaoxon for 96 h resulted in a 25 and a 30% decrease in the ratio of hydroxy...

The fate of malaoxon was studied in a susceptible and a resistant strain of house fly following topical application. Sublethal doses were used: 160 pmol for the S-strain (0.17 × LD50) and 1570 pmol for the R-strain (0.1 × LD50). The penetration rates are dose dependent and semilog plots of the...

Chiral separation mechanism determination and absolute configuration assignment are fundamental to the development of chiral stationary phases (CSPs) and the evaluation of both the enantioselective bioactivity and fate of chiral compounds. This work investigated the process of chiral separation ...

Malathion, one of the most widely applied insecticides, is still used in agriculture. There are many studies regarding its degradation under different experimental conditions, but few deal with its transformation products, i.e. malaoxon and isomalathion. Thus, malathion, malaoxon, isomalathion, ...

Butyraldehyde was aldolized with formaldehyde at 40–80°C over an anion-exchange resin catalyst in aqueous and methanolic solutions. The reaction mixture was analyzed with gas and liquid chromatography as well as nuclear magnetic resonance (NMR) spectroscopy. Two main products were detected: 2-...

A series of 1-(1-arylethylidene)thiosemicarbazide compounds and their analogues were synthesized and characterized by 1H NMR, MS. Their tyrosinase inhibitory activities were investigated by an assay based on the catalyzing ability of tyrosinase for the oxidation of l-DOPA, comparing with 4-metho...