Study on N-Demethylation of N,N-Dimethyl-4-aminoazobenzene and N-Nitrosamines by Prostaglandin H Synthase

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Title:Study on N-Demethylation of N,N-Dimethyl-4-aminoazobenzene and N-Nitrosamines by Prostaglandin H Synthase
Creators:
Stiborová, Marie
Frei, Eva
Schmeiser, Heinz H.
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 62, 6, pp. 971-980
Uncontrolled Keywords:Azo dyes, <i>N</i>-Nitrosamines, Radicals, <i>N</i>-Demethylation, Carcinogens, Prostaglandin H synthase

Abstract

The <i>in vitro</i> enzymatic metabolism of carcinogenic <i>N</i>,<i>N</i>-dimethyl-4-aminoazobenzene, <i>N</i>-nitroso-<i>N</i>-methylaniline and <i>N</i>-nitroso-<i>N</i>,<i>N</i>-dimethylamine was investigated using ram seminal vesicle microsomal prostaglandin H synthase. Both <i>N</i>-nitrosamines are not converted by the studied enzyme. Formaldehyde is produced by the prostaglandin H synthase catalyzed reaction from <i>N</i>,<i>N</i>-dimethyl-4-aminoazobenzene. Arachidonic acid and hydrogen peroxide serve as cofactors for the oxidation of <i>N</i>,<i>N</i>-dimethyl-4-aminoazobenzene. The apparent Michaelis constant and the maximal velocity values for <i>N</i>,<i>N</i>-dimethyl-4-aminoazobenzene as a substrate are 64 μmol/l and 51.2 nmol HCHO/min/mg protein, respectively. In addition to formaldehyde, <i>N</i>-methyl-4-aminoazobenzene and 4-aminoazobenzene, two unknown substances are the products of the <i>N</i>,<i>N</i>-dimethyl-4-aminoazobenzene oxidation. The oxidation of <i>N</i>,<i>N</i>-dimethyl-4-aminoazobenzene catalyzed by prostaglandin H synthase is inhibited by glutathione, ascorbate and NADH. The results suggest that prostaglandin H synthase metabolizes <i>N</i>,<i>N</i>-dimethyl-4-aminoazobenzene through a one-electron oxidation mechanism, giving rise to free radicals.

Title:Study on N-Demethylation of N,N-Dimethyl-4-aminoazobenzene and N-Nitrosamines by Prostaglandin H Synthase
Creators:
Stiborová, Marie
Frei, Eva
Schmeiser, Heinz H.
Uncontrolled Keywords:Azo dyes, <i>N</i>-Nitrosamines, Radicals, <i>N</i>-Demethylation, Carcinogens, Prostaglandin H synthase
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:62
Number:6
Page Range:pp. 971-980
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19970971UNSPECIFIED
ID Code:1178
Item Type:Article
Deposited On:06 Feb 2009 17:07
Last Modified:06 Feb 2009 16:07

Citation

Stiborová, Marie; Frei, Eva; Schmeiser, Heinz H. (1997) Study on N-Demethylation of N,N-Dimethyl-4-aminoazobenzene and N-Nitrosamines by Prostaglandin H Synthase. Collection of Czechoslovak Chemical Communications, 62 (6). pp. 971-980. ISSN 0010-0765

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