The nature of molybdenum cofactor in the bacterial enzyme dimethyl sulfoxide reductase has been investigated by application of alkylation conditions that convert the molybdenum cofactor in chicken liver sulfite oxidase and milk xanthine oxidase to the stable, well-characterized derivative [di(carboxamidomethyl)]molybdopterin. The alkylated pterin obtained from dimethyl sulfoxide reductase was s...

The conformational behavior of monosubstituted tri-methylsilyle ethynyl Derivative of Cal ix[4]arene as a newgeneration of Caliarene was compared with tetra alkylated calyx[4]arene. The most important conformationalphenomena in these compounds which are pinched cone interconversion process were done by semi-empiricalmethod and ab initio calculations with Gaussian 98w programming.

A number of 3-amino-1, 2, 4-triazin-5 (2H)- ones(1) were synthesized and condensed with a-haloketones to give 2,6-disubstituted imidazo [1, 2-b] [1, 2, 4]-triazin-3 (4H)-ones (2). These compounds were reacted further with a - haloketones to yield N-alkylated products (3).

Iodoacetamide inactivates glycogen phosphorylase and causes it to dissociate into monomers of 92,500 molecular weight. Three -SH groups on each monomer are alkylated, but the first reacts as rapidly as do model compounds and its alkylation does not cause inactivation. The remaining two -SH groups are alkylated several hundred times slower, at rates comparable to the loss of activity. The three ...

1. The incorporation of methyl groups into histones from dimethylnitrosamine and from methionine was studied by injection of the labelled compounds, isolation of rat liver and kidney histones, and analysis of hydrolysates by column chromatography. 2. Labelled methionine gave rise to labelled in-N-methyl-lysine, di-in-N-methyl-lysine and an amino acid presumed to be omega-N-methyl-arginine. 3. A...

This study reports a rapid assay to distinguish depurination from other forms of alkaline-labile lesions induced in DNA by alkylating agents. Covalently closed circular duplex PM2 DNA was treated with various alkylating agents such as N-methyl-N-nitrosourea, dimethyl sulfate, methyl methanesulfonate, N-ethyl-N-nitrosourea, diethyl sulfate, and ethyl methanesulfonate at pH 6.5. Apurinic sites an...

We collected surface sediment samples from 174 locations in India, Indonesia, Malaysia, Thailand, Vietnam, Cambodia, Laos, and the Philippines and analyzed them for polycyclic aromatic hydrocarbons (PAHs) and hopanes. PAHs were widely distributed in the sediments, with comparatively higher concentrations in urban areas (Sigma PAHs: approximately 1000 to approximately 100,000 ng/g-dry) than in r...

Lead is an important heavy metal used in many industrial processes. It plays an important role in the pathogenesis of both acute and chronic toxicity. Mechanics have a high risk of benzene exposure but tend to be a forgotten occupational group in Thailand. In this study, monitoring of lead exposure by anodic stripping voltammetry (ASV) determination of blood lead levels was conducted for 69 sub...

The impact of crude oil pollution on early life stages (ELS) of fish, including larvae and embryos, has received considerable attention in recent years. Of the organic components present in crude oil, polycyclic aromatic hydrocarbons (PAHs) are considered the main class of compounds responsible for toxic effects in marine organisms. Although evidence suggests that they are more toxic, alkylated...

background: nanotechnology is a new approach that has been lionized in recent years. one of its applications is its consumption as an absorbent. in this study, the single-wall carbon nanotubes (swcnts) were used as an absorbent for sampling benzene in the air. materials and methods: for this study, swcnts manufactured by iran and skc’s activated charcoal were used for sampling benzene vapors. p...