Reaction of a nucleobase with nitrosonium ion leads to its diazotization. Due to the instability,the nucleobase-diazonium assumingly falls in dediazotization and successive ring openingreactions. The resulting intermediate of the ring opening reaction is able to covalently cross-linkthe opposite strands of DNA. To examine this assumption for cytosine, some 4-amino-5-cyanopyrimidines were synthe...

ABSTRACT. The azo dye of 1,3-dimethylxanthine, namely 8-[(4-acetyl phenyl azo)]-1,3-dimethylxanthine (APAX), was prepared in two steps. first step included the formation diazonium salt by reacting 4-aminoacetophenone with sodium nitrite NaNO2 under acidic conditions and completing diazotization process while maintaining a low temperature below 5 °C. resulting reacted 1,3-dimethylxanthine compou...

In this study, colorimetric method and high-performance liquid chromatographic (HPLC) method were improved and established, respectively, in order to minimize analytical errors in determination of para-aminohippuric acid (PAH) in rat urine and plasma. In terms of the colorimetric method, an operative step following addition of Tsuda reagent was modified as follows: after the addition of Tsuda r...

Nitrate in serum and urine was assayed by a modification of the cadmium-reduction method; the nitrite produced was determined by diazotization of sulfanilamide and coupling to naphthylethylene diamine. After samples were deproteinized with Somogyi reagent, the nitrate was reduced by Cu-coated Cd in glycine buffer at pH 9.7 (2.5 to 3 g of Cd granules for a 4-mL reaction mixture). The reduction f...

Chemicals-o-Aminophenyl glucosiduronic acid was kindly supplied by Dr. R. T. Williams, St. Mary’s Hospital Medical School, London. oAminobenzoyl and p-aminobenzoyl glucosiduronic acids were prepared enzymatically with UDP-glucuronic acid’ and aglycone (5). Phenolphthalein glucosiduronic acid and bacterial P-glucuronidase were obtained from the Sigma Chemical Company, St. Louis, Missouri. UDP-gl...

A competitive indirect enzyme-linked immunosorbent assay (ciELISA) for the organophosphorus insecticide acephate, O,S-dimethyl acetylphosphoramidothioate, was developed using a polyclonal antibody. Five different haptens mimicking the analyte were synthesized and conjugated with the carrier proteins bovine serum albumin (BSA) and keyhole limpet hemocyanin (KLH) by the N-hydroxysuccinimide activ...