Peroxidases from Tulip Bulbs (Tulipa fosteriana, L.) Oxidize Xenobiotics NNitrosodimethylamine and N-Nitroso-N-methylaniline in vitro

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Title:Peroxidases from Tulip Bulbs (Tulipa fosteriana, L.) Oxidize Xenobiotics NNitrosodimethylamine and N-Nitroso-N-methylaniline in vitro
Creators:
Stiborová, Marie
Hansíková, Hana
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 62, 11, pp. 1804-1814
Uncontrolled Keywords:Exogenous chemicals, <i>N</i>-Nitrosamines, Enzyme kinetics, Enzymatic oxidation, <i>N</i>-Demethylation, Plants

Abstract

Tulip bulbs (<i>Tulipa fosteriana</i>, L.) contain peroxidases catalyzing the oxidation of the xenobiotics <i>N</i>-nitrosodimethylamine (NDMA) and <i>N</i>-nitroso-<i>N</i>-methylaniline (NMA). Three anionic (A<sub>1</sub>, A<sub>2</sub>, A<sub>3</sub>) and four cationic (B, C, D, E) peroxidases were purified from this tissue, partially characterized and used for kinetic studies. Demethylation of NDMA and NMA producing formaldehyde is catalyzed by one anionic (A<sub>1</sub>) and three cationic (C, D, E) peroxidases. The oxidation of NDMA by tulip peroxidases exhibits the Michaelis-Menten kinetics. The apparent Michaelis constant and the maximal velocity values for this substrate were determined. On the other hand, non-Michaelian kinetics for the NMA oxidation were observed with tulip peroxidases. The most abundant cationic peroxidase (peroxidase C) was used for detailed enzymatic studies. In addition to formation of formaldehyde, methylaniline, aniline, 4-aminophenol and phenol were found to be metabolites formed from NMA. Phenol was formed presumably by <i>N</i>-demethylation <i>via</i> a benzenediazonium ion, while methylaniline, aniline and 4-aminophenol were products of denitrosation of the substrate. The efficiencies of plant peroxidases to oxidize NDMA and NMA <i>in vitro</i> are compared with those of cytochromes P450 and discussed.

Title:Peroxidases from Tulip Bulbs (Tulipa fosteriana, L.) Oxidize Xenobiotics NNitrosodimethylamine and N-Nitroso-N-methylaniline in vitro
Creators:
Stiborová, Marie
Hansíková, Hana
Uncontrolled Keywords:Exogenous chemicals, <i>N</i>-Nitrosamines, Enzyme kinetics, Enzymatic oxidation, <i>N</i>-Demethylation, Plants
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:11
Page Range:pp. 1804-1814
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19971804UNSPECIFIED
ID Code:1254
Item Type:Article
Deposited On:06 Feb 2009 17:07
Last Modified:06 Feb 2009 16:08

Citation

Stiborová, Marie; Hansíková, Hana (1997) Peroxidases from Tulip Bulbs (Tulipa fosteriana, L.) Oxidize Xenobiotics NNitrosodimethylamine and N-Nitroso-N-methylaniline in vitro. Collection of Czechoslovak Chemical Communications, 62 (11). pp. 1804-1814. ISSN 0010-0765

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