The oxidation of pyrene and benzo[<i>a</i>]pyrene by nonbasidiomycete soil fungi

Launen, Loren A.; Pinto, Linda J.; Wiebe, Christine; Kiehlmann, Eberhard; Moore, Margo M.

doi:10.1139/m95-064

Cited by 95 publications

(50 citation statements)

References 34 publications

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“…The compounds in peaks 2 and 3 were readily identified by their NMR patterns, which were both simplified because of the symmetry in the molecules. Furthermore, the NMR and UV spectra of peaks 2 and 3 matched those of 1,6 and 1,8 di-OH pyrene reported in the literature (62,63).…”

Section: Characterization Of Oxidation Products Of ␣Nf and Pyrene-supporting

confidence: 79%

Cooperativity in Oxidation Reactions Catalyzed by Cytochrome P450 1A2

Sohl

Isin

Eoff

et al. 2008

Journal of Biological Chemistry

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Rabbit liver cytochrome P450 (P450) 1A2 was found to catalyze the 5,6-epoxidation of ␣-naphthoflavone (␣NF), 1-hydroxylation of pyrene, and the subsequent 6-, 8-, and other hydroxylations of 1-hydroxy (OH) pyrene. Plots of steady-state rates of product formation versus substrate concentration were hyperbolic for ␣NF epoxidation but highly cooperative (Hill n coefficients of 2-4) for pyrene and 1-OH pyrene hydroxylation. When any of the three substrates (␣NF, pyrene, 1-OH pyrene) were mixed with ferric P450 1A2 using stopped-flow methods, the changes in the heme Soret spectra were relatively slow and multiphasic. Changes in the fluorescence of all of the substrates were much faster, consistent with rapid initial binding to P450 1A2 in a manner that does not change the heme spectrum. For binding of pyrene to ferrous P450 1A2, the course of the spectra revealed sequential changes in opposite directions, consistent with P450 1A2 being involved in a series of transitions to explain the kinetic multiphasicity as opposed to multiple, slowly interconverting populations of enzyme undergoing the same event at different rates. Models of rabbit P450 1A2 based on a published crystal structure of a human P450 1A2-␣NF complex show active site space for only one ␣NF or for two pyrenes. The spectral changes observed for binding and hydroxylation of pyrene and 1-OH pyrene could be fit to a kinetic model in which hydroxylation occurs only when two substrates are bound. Elements of this mechanism may be relevant to other cases of P450 cooperativity.

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Section: Characterization Of Oxidation Products Of ␣Nf and Pyrene-supporting

confidence: 79%

Cooperativity in Oxidation Reactions Catalyzed by Cytochrome P450 1A2

Sohl

Isin

Eoff

et al. 2008

Journal of Biological Chemistry

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“…Launen et al (20), reported that microorganisms degrade more efficiently PAHs with a lower number of aromatic rings in the molecule. Strains 984 degraded anthracene (64% ± 10%), which possesses 3 aromatic rings, as efficiently as naphthalene, which has 2 aromatic rings (69% ± 10%).…”

Section: Resultsmentioning

confidence: 99%

Biodegradation of polycyclic aromatic hydrocarbons by soil fungi

Clemente¹,

Anazawa²,

Durrant³

2001

Braz. J. Microbiol.

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Thirteen deuteromycete ligninolytic fungal strains were grown in media containing polycyclic aromatic hydrocarbons (PAHs), for 6 and 10 days. The PAHs were added directly with the inocula or on the third day of cultivation. A selection of the best strains was carried out based on the levels of degradation of the PAHs and also on the ligninolytic activities produced by the fungi. The selected strains were cultivated for 3, 6, 9, 12 and 15 days in the PAHs-containing media. Degradation of PAHs, as measured by reversed-phase HPLC on a C18 column, varied with each strain as did the ligninolytic enzymes present in the culture supernatants. Highest degradation of naphthalene (69%) was produced by the strain 984, having Mn-peroxidase activity, followed by strain 870 (17%) showing lignin peroxidase and laccase activities. The greatest degradation of phenanthrene (12%) was observed with strain 870 containing Mn-peroxidase and laccase activities. When anthracene was used, the strain 710 produced a good level of degradation (65%).

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“…Also, non-ligninolytic fungi, such as Cunninghamella elegans, Penicillium janthinellum, Aspergillus niger and Syncephalastrum sp., are able to transform a variety of PAHs, including chrysene and benzo(a)pyrene, to polar metabolites [13,14,23,24]. These microorganisms carry out a monooxygenation of the PAH molecules by the intracellular cytochrome P-450 dependent oxidase system [25].…”

Section: Introductionmentioning

confidence: 99%