2-Aminofluorene bioactivation by human term placental peroxidase.

  title={2-Aminofluorene bioactivation by human term placental peroxidase.},
  author={K. Murthy and P. Joseph and A. Kulkarni},
  journal={Teratogenesis, carcinogenesis, and mutagenesis},
  volume={15 3},
Earlier investigations from our laboratory demonstrated that human term placental peroxidase (HTPP) is capable of metabolism of xenobiotics and endogenous compounds. In this study, purified HTPP was found to bioactivate 2-aminofluorene (2-AF) in the presence of H2O2. 2-AF oxidation was studied spectrophotometrically while radiometry was employed to assess the bioactivation. The rate of oxidation and covalent binding to protein and DNA was dependent upon the pH of the reaction medium and the… Expand
4 Citations
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
The role of xenobiotic-metabolizing enzymes in the placenta: a growing research field
This review provides a brief description of the human placental structure and function, the main drug and xenobiotic transporters and metabolizing enzymes, placenta-metabolized substrates, and alterations in gene expression that the exposure to xenobiotics may cause. Expand


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
Lipoxygenase: a new pathway for 2-aminofluorene bioactivation.
The results strongly suggest that lipoxygenase is capable of 2-AF metabolism and this may represent another pathway for bioactivation of arylamines. 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
Xenobiotic oxidation during early pregnancy in man: peroxidase catalysed chemical oxidation in conceptual tissues.
The results suggest that peroxidase may be one of the major pathways of xenobiotic oxidation present in organogenesis-stage human conceptual tissues influencing the toxicity of chemicals to which the developing embryo is exposed. 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
The oxidation of 2-aminofluorene by prostaglandin endoperoxide synthetase. Comparison with other peroxidases.
Results suggest that 2-AF is oxidized to an electrophilic intermediate(s) by prostaglandin endoperoxide synthetase, which either binds covalently to tissue macromolecules or is further rapidly oxidizing to 2-nitrofluorene and azofluorene. Expand
Cytochrome P-450- and flavin-containing monooxygenase-catalyzed formation of the carcinogen N-hydroxy-2-aminofluorene and its covalent binding to nuclear DNA.
The levels of AF bound to hepatic nuclear DNA reported in vivo suggest that the nonenzymatic reaction of N-OH-AF with nuclear DNA may be sufficient to account for a substantial portion of the observed in vivo binding of this carcinogen. 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
On the mechanism of peroxidation of uric acids by hemoproteins.
The studies described herein show that any purine with an unsubstitued N-7 or N-9 position and an 8-0~0 substituent is susceptible to peroxidation in the presence of hemoprotein (or hematin) and peroxide. 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