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Biotransformation of the polycyclic aromatic hydrocarbon pyrene in the marine polychaete Nereis virens
Author(s) -
Jørgensen Anne,
Giessing Anders M. B.,
Rasmussen Lene Juel,
Andersen Ole
Publication year - 2005
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/05-047r.1
Subject(s) - pyrene , biotransformation , glucuronidation , chemistry , polycyclic aromatic hydrocarbon , hydroxylation , benzopyrene , glucuronide , biochemistry , benzo(a)pyrene , environmental chemistry , enzyme , microsome , metabolism , organic chemistry
In vivo and in vitro biotransformation of the polycyclic aromatic hydrocarbon (PAH) pyrene was investigated in the marine polychaete Nereis virens . Assays were designed to characterize phase I and II enzymes isolated from gut tissue. High‐pressure liquid chromatography measurement of 1‐hydroxypyrene, pyrene‐1‐glucuronide, pyrene‐1‐sulfate, and pyrene‐1‐glucoside appeared to be a sensitive method for estimating the activity of pyrene hydroxylase, glucuronosyl transferase, and sulfotransferase. Total pyrene in gut tissue after a 5‐d exposure to 10 μg/g dry weight pyrene constituted 65% pyrene‐1‐glucuronide, 12% pyrene‐1‐sulfate, 2% pyrene‐1‐glucoside, 4% 1‐hydroxypyrene, and 17% pyrene, indicating that glucuronidation is the prominent phase II pathway in this organism. Only pyrene hydroxylase activity was induced significantly after pre‐exposure to sediment‐associated pyrene (10 μg/g dry wt). Apparent kinetic parameters were determined for all enzymatic reactions. Glucuronidation was confirmed as being the prominent phase II reaction, based on its high apparent maximum velocity ( V max(a) ). Sulfation had the lowest apparent Michaelis constant ( K m(a) ), indicating high specificity. Apparent kinetic parameters for pyrene hydroxylase activity were changed after induction with pyrene. Induced worms showed increased V max(a) and decreased K m(a) compared to noninduced worms, indicating that the relative amount of the cytochrome P450 enzyme(s) responsible for pyrene hydroxylation is increased. Our findings show that N. virens has a high biotransformation capacity for PAHs, with inducible pyrene hydroxylase activity, and that the most prominent phase II pathway in this organism is glucuronidation.