PEROXIDASE METABOLISM OF THE URINARY-BLADDER CARCINOGEN "2-AMINO-4-(5-NITRO-2-FURYL)THIAZOLE

  • 1 January 1983
    • journal article
    • research article
    • Vol. 43  (4) , 1518-1522
Abstract
Metabolism of 2-amino-4-(5-nitro-2-furyl)thiazole (ANFT) by a variety of different peroxidases was examined [using solubilized ram seminal vesicles]. Metabolism of ANFT was measured by the binding of radiolabeled substrates to protein and DNA. Prostaglandin hydroperoxidase but not horseradish peroxidase, lactoperoxidase, or chloroperoxidase metabolically activated ANFT. All 4 peroxidases catalyzed the binding of benzidine to protein and DNA. With peroxide substrates, peroxidase-catalyzed binding of both carcinogens was observed with or without molecular oxygen. Arachidonic acid-dependent binding of ANFT and benzidine by prostaglandin endoperoxide synthetase was inhibited by anaerobic conditions and aspirin. Chloroperoxidase activation of benzidine was also inhibited by aspirin. Vitamin E inhibited activation of both carcinogens by all enzymes examined. Prostaglandin hydroperoxidase-catalyzed binding of benzidine to protein was inhibited by the 5-nitrofurans ANFT and 3-hydroxymethyl-1-{[3-(5-nitro-2-furyl)allydidene]amino]}hydantoin and acetaminophen, while only acetaminophen inhibited horseradish peroxidase-catalyzed binding. These results indicate that different peroxidases may exhibit specificity with respect to their activation of carcinogens. Only prostaglandin hydroperoxidase activated the 5-nitrofuran ANFT, while a number of peroxidases activated the aromatic amine benzidine.