Polycyclic aromatic hydrocarbons biotransformation

Polycyclic aromatic hydrocarbons Biotransformation, immobilization Moderate Low... 

MacGillivray AR, MP Shiaris (1993) Biotransformation of polycyclic aromatic hydrocarbons by yeasts isolated from coastal sediments. Appl Environ Microbiol 59 1613-1618. 

Warshawsky D, T Cody, M Radike, R Reilman, B Schumann, K LaDow, J Schneider (1995) Biotransformation of benzo[a]pyrene and other polycyclic aromatic hydrocarbons and heterocyclic analogues by several green algae and other algal species under gold and white light. Chem-Biol Interact 97 131-148. 

Allen CCR, DR Boyd, F Hempenstall, MJ Larkin, ND Sharma (1999) Contrasting effects of a nonionic surfactant on the biotransformation of polycyclic aromatic hydrocarbons to cw-dihydrodiols by soil hacierva.. Appl Environ Microbiol 65 1335-1339. 

Frank, A.P., Landrum, P.F., Eadie, B. J. (1986) Polycyclic aromatic hydrocarbon rates of uptake, depuration, and biotransformation by Lake Michigan Stylodrilus heringianus. Chemosphere 15, 317-330. 

This type of substrate-substrate interaction may be especially important for contaminants introduced as mixtures in the environment. One example is the mix of polycyclic aromatic hydrocarbons co-introduced in oil spills or in coal tar wastes. Laboratory observations of the biodegradation of such hydrocarbons show that some of these components can inhibit the removal of other compounds in the mix (Guha et al., 1999). Such results indicate that the rate of a particular chemical s biotransformation may be a function of factors such as the presence of competing substrates interacting with the same enzyme systems. 

By far the major portion of biotransformation is carried out in the liver by cytochrome P-450 (P-450), which is a collective term for a group of related enzymes or isoenzymes that are responsible for the oxidation of numerous drugs endogenous substances such as fatty acids, prostaglandins, steroids, and ketones and carcinogens such as polycyclic aromatic hydrocarbons, nitrosamines, hydrazines, and arylamines. 

The program is reported to carry out simple Hiickel molecular orbital calculations to determine the relative sensitivity of aromatic carbon atoms to oxidation and the relative stability of keto and enol tautomers. Klopman et al. (1999) have reported that for polycyclic aromatic hydrocarbons, adequate reactivity is an essential but not sufficient condition for enzyme catalyzed reaction. The accessibility of the reactive site (i.e., the absence of steric hindrance) was also found to be important. Genetic algorithms have been used to optimize the performance of the biotransformation dictionary by treating the initial priority scores set by expert assessment as adjustable parameters (Klopman et al., 1997). 

Metabolism databases and several predictive software packages also have been reviewed.A knowledge-based expert system for the prediction of phase I and II biotransformations called META was developed on the VAX/VMS platform,META contains over 750 biotransformations based on substrnctnres and qnantnm mechanical calculations that gave excellent predictions on test data and have been optimized using a genetic algorithm to perform better than human experts.However, when used to predict the metabolism of 42 polycyclic aromatic hydrocarbons (PAHs), META overpredicted 29 and missed 8 of 72 experimentally observed epoxidations, and missed 27 of 49 experimentally observed hydroxylations. ... 

Broman D, Naf C, Windburn I, et al. 1990. An in sak/study on the distribution biotransformation and flux of polycyclic aromatic hydrocarbons (PAHs) in an aquatic food chain seston Mytilus edulis L and Somateria moiiissimaL from the Baltic An ecotoxicological perspective. Environ Toxicol Chem 9(4) 429-442. 

Nyholm, S. H., Alexander, J., Lundanes, E., Frandsen, H., Andersson, R., Grivas, S., Nesnow, S., and Holme, J. A. (1996). Biotransformation of die cyclopenta-fused polycyclic aromatic hydrocarbon benz[/]aceanthrylene in isolated rat Uver cell Identification of nine new metabolites. Carcinogenesis 17, 1111-1120. 

Attention has already been made to the formation of glycoside and sulfate conjugates of phenolic metabolites during the biotransformation of polycyclic aromatic hydrocarbons by fungi (Section 6.2.2). Formation of sulfate esters is not, however, limited to fungal systems since this has been observed, for example, following 4 -hydroxylation of 5-hydroxyflavone in Streptomyces fulvissimus (Ibrahim and Abul-Hajj 1989), and the enzyme has been partly purified from a Eubacterium sp. (Koizumi et al. 1990). 

Campbell ME, Grant DM, Inaba T, Kalow W.Biotransformation of caffeine, paraxanthine, theophylline, and theobromine by polycyclic aromatic hydrocarbon-inducible C5 tochrome(s) P-450 in human liver microsomes. Drug Metab Dispos 1987 15 237-249. 

James MO (1989a) Biotransformation and disposition of PAH in aquatic invertebrates. In Varanasi U (ed) Metabolism of polycyclic aromatic hydrocarbons in the aquatic environment. CRC Press, Boca Raton, Florida, pp 69-91... 

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