Xenobiotic oxidation during early pregnancy in man: peroxidase catalysed chemical oxidation in conceptual tissues.

  title={Xenobiotic oxidation during early pregnancy in man: peroxidase catalysed chemical oxidation in conceptual tissues.},
  author={P. Joseph and S. Srinivasan and A. Kulkarni},
  journal={Xenobiotica; the fate of foreign compounds in biological systems},
  volume={24 7},
1. A membrane-bound peroxidase activity was isolated and purified from pooled samples of human intrauterine tissue (embryo, placenta, amnion, chorion and uterine decidua) of 4-6 weeks of gestation. 2. The H2O2-dependent guaiacol oxidation catalysed by the purified peroxidase exhibited a specific activity of 10.82 +/- 1.81 mumol/min/mg protein. 3. The optimum conditions required for guaiacol oxidation catalysed by the peroxidase included 18 mM guaiacol, 400 microM H2O2, pH 9.0, and 2 micrograms… Expand
Xenobiotic metabolism in humans during early pregnancy: peroxidase-mediated oxidation and bioactivation of 2-aminofluorene.
2-AF oxidation was found to be enzymatic in nature and a significant decline in the rate of both oxidation and bioactivation of 2-AF was observed in the presence of classical peroxidase inhibitors, KCN and NaN3. Expand
Peroxidative xenobiotic oxidation by partially purified peroxidase and lipoxygenase from human fetal tissues at 10 weeks of gestation.
The ability of partially purified peroxidase and lipoxygenase from human fetal tissues at 10 weeks of gestation to oxidize selected xenobiotics in vitro is reported to suggest thatperoxidases and lip oxygengenase may be important pathways for per oxidative xenobiotic oxidation in human fetal tissue. Expand
2-Aminofluorene bioactivation by human term placental peroxidase.
The results strongly suggest that peroxidase may be one of the important pathways responsible for the bioactivation of arylamines in human term placenta. Expand
Oxidation of eugenol by purified human term placental peroxidase.
The results suggest that eugenol may undergo peroxidative metabolism in human placenta. Expand
Purification and partial characterization of peroxidase from human term placenta of non-smokers: metabolism of benzo(a)pyrene-7, 8-dihydrodiol.
Purified HTPP differed from eosinophil peroxidase in all physico-chemical properties indicating that it is not of eos inophil origin, but may represent a distinct, constitutive peroxidsase in human placenta. Expand
Human term placental lipoxygenase-mediated N-demethylation of phenothiazines and insecticides in the presence of linoleic acid.
The ability of polyunsaturated free fatty acids to support N-demethylation of xenobiotics via the lipoxygenase pathway is shown to be able to reduce the production of formaldehyde by HTPLO. Expand
Comparison of cytochrome P450- and peroxidase-dependent metabolic activation of the potent carcinogen dibenzo[a,l]pyrene in human cell lines: formation of stable DNA adducts and absence of a detectable increase in apurinic sites.
Results indicate that metabolic activation of DB[a,l]P by cytochrome P450 enzymes to diol epoxides that form stable DNA adducts, rather than one-electron oxidation catalyzed either by cy tochrome P 450 enzymes or peroxidases to form AP sites, is responsible for the high carcinogenic activity of DB,[a, l]P. Expand
Sites Adducts and Absence of a Detectable Increase in Apurinic ] pyrene in Human Cell Lines : Formation of Stable DNA a , l Metabolic Activation of the Potent Carcinogen Dibenzo [ Comparison of Cytochrome P 450-and Peroxidase-dependent Updated
The potent carcinogen dibenzo[ a,l]pyrene (DB[a,l]P) has been reported to form both stable and depurinating DNA adducts upon activation by cytochrome P450 enzymes and/or cellular peroxidases. OnlyExpand


Peroxidase: a novel pathway for chemical oxidation in human term placenta.
The results suggest that peroxidase may be a major enzyme in human term placenta capable of oxidation of endogenous chemicals and xenobiotics. Expand
Placental peroxidase--further purification of the enzyme and oxidation of thiobenzamide.
Human term placental peroxidase from non-smoking women was purified by extraction of the membrane fraction with 0.5 M Ca2+ followed by affinity chromatography on concanavalin A, hydrophobic Chromatography on phenyl sepharose CL-4B and gel filtration chromatographyon sephacryl S-200 columns suggesting apparent homogeneity of the protein. Expand
Partial purification and characterization of a peroxidase activity from human placenta.
The presence of peroxidase activity was observed in human term and pre-term placenta and HTPP appears to be a membrane-bound glycoprotein, suggesting an endogenous origin. Expand
Peroxidase, an alternate pathway to cytochrome P-450 for xenobiotic metabolism in skin: partial purification and properties of the enzyme from neonatal rat skin.
Subcellular distribution studies indicated the activity to be highest and comparable in nuclei and mitochondria, lowest in microsomes, and absent in cytosol, while the combination of 2 mM N-ethylmaleimide and 10% (w/v) glycerol was found to be optimal for preservation of activity. Expand
Characteristics of estrogen-induced peroxidase in mouse uterine luminal fluid
It was not possible to exclude eosinophil peroxidase, brought to the uterus after estrogen stimulation, as being the source of perxidase activity in uterine luminal fluid, but NADPH, ascorbate, and cytochrome c inhibited both Luminal fluid and uterine tissue peroxIDase activity to the same extent. Expand
Generality of oestrogen stimulation of peroxidase activity in growth responsive tissues
The generality and specificity of oestrogen regulation of peroxidase activity is reported on, which indicates a uterine origin for the enzyme. Expand
Human embryonic cytochrome P450S: phenoxazone ethers as probes for expression of functional isoforms during organogenesis.
Results were consistent with the concept that conceptal-specific P450 isoforms participate in the human embryonic O-dealkylation/debenzylation probe reactions investigated. Expand
P-450 Cytochromes in the Human Placenta: Oxidations of Xenobiotics and Endogenous Steroids
The purpose of this article is to provide the reader with a concise view of current concepts concerning the family of P-450 hemoproteins as they exist and function in the human placenta. The subjectExpand
Peroxidase activity in the mouse uterus, placenta and fetus during pregnancy.
: Changes in peroxidase activity during pregnancy were examined in CD-1 mice. Peroxidase activity was measured with guaiacol as the substrate in uterine extracts of nonpregnant mice and in uterine,Expand
Studies on peroxidase-catalyzed formation of progesterone
Subcellular fractions of pregnant rabbit ovary at day six of gestation catalysed the formation of progesterone from pregnenolone (3 beta-hydroxy-5-pregnen-20-one) and ascorbate appears to perform a catalytic role in this conversion. Expand