Open Access Green möglich sobald Postprint bei der ZB eingereicht worden ist.
Enzymatic synthesis of bromo- and chlorocarbazoles and elucidation of their structures by molecular modeling.
Environ. Sci. Pollut. Res. 20, 8996-9005 (2013)
3-Chlorocarbazole, 3,6-dichlorocarbazole, dibromocarbazole, and 1,3,6,8-tetrabromocarbazole are emerging environmental contaminants which have been detected recently in water, sediment, and soil samples. However, their sources and occurrence have not been explained. Here, we report an enzymatic synthesis of bromo- and chlorocarbazoles by chloroperoxidase from Caldariomyces fumago in water. Density functional theory (DFT) method was used to predict the most stable products. Carbazole and chloroperoxidase were assayed in vitro in the presence of hydrogen peroxide, bromide, and chloride ions in different substrate ratio treatments against constant and varying enzyme concentrations. Halogenated carbazoles formed were identified by high-resolution gas chromatography coupled to mass spectrometry. In all treatments, bromination and chlorination took place, but the composition and concentration of compounds formed varied from one treatment to another. Mono-, di-, tri-, and tetra-substituted bromo- and chlorocarbazoles which include the reported environmental contaminants were synthesized. 3-Substituted and 3,6-substituted congeners were relatively higher in concentration. Enzyme concentration did not favor preferential formation of any of the compounds synthesized. However, their synthesis was influenced by halide concentration. Congeners with bromine and chlorine at position of C-3, C-3,6, C-1,3,6, and C-1,3,6,8 were calculated as the stable intermediate sigma complexes by DFT method. Regioselectivity in halogenation is discussed and hypothesis of the likely stable products in the environment explained. This study provides evidence that bromo- and chlorocarbazoles reported previously can be formed enzymatically in the environment, demonstrating the need to consider aromatic pollutants transformation and their potential toxicity enhancements in the management of water pollution and contaminated sites.
Impact Factor
Scopus SNIP
Web of Science
Times Cited
Times Cited
Scopus
Cited By
Cited By
Altmetric
2.618
1.222
43
45
Anmerkungen
Besondere Publikation
Auf Hompepage verbergern
Publikationstyp
Artikel: Journalartikel
Dokumenttyp
Wissenschaftlicher Artikel
Schlagwörter
Bromocarbazoles; Chlorocarbazoles; Chloroperoxidase; Density functional theory (DFT) calculations; Enzymatic bromination and chlorination; Regioselectivity in halogenation; Aromatic-hydrocarbons ; Hydrogen-peroxide ; Chloroperoxidase ; Chlorination ; Carbazole ; Haloperoxidases ; Identification ; Biosynthesis ; Halogenation ; Water
Sprache
englisch
Veröffentlichungsjahr
2013
HGF-Berichtsjahr
2013
ISSN (print) / ISBN
0944-1344
e-ISSN
1614-7499
Zeitschrift
Environmental Science and Pollution Research
Quellenangaben
Band: 20,
Heft: 12,
Seiten: 8996-9005
Verlag
Springer
Begutachtungsstatus
Peer reviewed
Institut(e)
PPM-MEX-Molecular EXposomics (MEX)
POF Topic(s)
30202 - Environmental Health
Forschungsfeld(er)
Environmental Sciences
PSP-Element(e)
G-509100-001
PubMed ID
23757025
WOS ID
WOS:000327498600067
Scopus ID
84891161163
Erfassungsdatum
2013-08-01