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- 2009 (2) (entfernen)
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- Englisch (2)
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- Flammschutzmittel (1)
- Molecular modeling (1)
- Thyroxin (1)
The binding affinities of the six main hexabromocyclododecane (HBCD) stereoisomers and all of their possible 48 allylic pentabromocyclododecene (PBCD) metabolites to the endocrinous human transthyretin receptor (hTTR) were investigated and compared to the natural binder thyroxine, and the two brominated diphenyl ethers BDE-47 and 3-hydroxy-BDE-47. The endocrine disrupting potency was approximated by a combination of two methods: a surface matching with the natural binder thyroxine (T4) followed by approximation of free binding energies for various binding modes within hTTR. The results indicate slightly higher binding affinities for both BDE structures than for T4 itself and similarly high affinities for two trans-configurated PBCD isomers. For many other PBCD isomers, intermediate values were computed, whereas all HBCD diastereomers yielded significantly lower binding affinities.
1,2,5,6,9,10-hexabromocyclododecane (HBCD), a widely used flame retardant, is an ubiquitous contaminant in
the environment. Still, only little is known about the distribution and behavior in the environment such as
bioaccumulation or biotransformation of HBCD stereoisomers. In order to investigate enrichment and possible
bioisomerization of HBCD stereoisomers, Mirror Carps were exposed to pure (+)- and (-)-γ-HBCD, randomly
sampled after a predefined specific period and subjected to enantiomer-specific determination of α-, β-, and γ-
HBCD. No evidence for the isomerization of HBCD stereoisomers was observed in Mirror Carp fillets.