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1.
Bull Environ Contam Toxicol ; 81(1): 1-6, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18461267

ABSTRACT

Quantitative structure-activity relationship (QSAR) models for fungal laccase-catalyzed degradation of different hydroxylated polychlorinated biphenyls (OH-PCBs) were developed using some fundamental quantum chemical descriptors. The cross-validated Q(2)(cum )values for the two optimal QSAR models are as high as 0.958 and 0.961 for laccases from Trametes versicolor and Pleurotus ostreatus, respectively, indicating good predictive abilities for laccase-catalyzed degradation of OH-PCBs. Results from this study show that increasing heat of formation (DeltaH(f)) and frontier molecular orbital energy (i.e. E(LUMO) + E(HOMO)) values or decreasing frontier molecular orbital energy (i.e. E(HOMO-1)) and core-core repulsion energy (CCR) values leads to the increase of OH-PCB degradation rates by laccases.


Subject(s)
Basidiomycota/enzymology , Biodegradation, Environmental , Laccase/metabolism , Pleurotus/enzymology , Polychlorinated Biphenyls/metabolism , Algorithms , Hydroxylation , Kinetics , Least-Squares Analysis
3.
SAR QSAR Environ Res ; 17(2): 173-82, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16644556

ABSTRACT

By partial least squares (PLS) regression analysis, a quantitative structure-property relationship (QSPR) model was developed for photodegradation half-life (t1/2) of polychlorinated biphenyls (PCBs) in n-hexane solution under UV irradiation. Quantum chemical descriptors computed by PM3 Hamiltonian were used as predictor variables. The cross-validated value for the optimal QSPR model was 0.589, indicating good predictive capability for log t1/2 values of PCBs in n-hexane. The QSPR results show that standard heat of formation (DeltaHf), total energy (TE), and molecular weight (Mw) have dominant effect on t1/2 values of PCBs in n-hexane. Increasing DeltaHf and TE values or decreasing Mw values of the PCBs leads to decrease of log t1/2 values. In addition, increasing the largest negative atomic charge on a carbon atom and dipole moment of the PCBs leads to decrease of log t1/2 values.


Subject(s)
Models, Chemical , Polychlorinated Biphenyls/radiation effects , Quantitative Structure-Activity Relationship , Environmental Pollutants/radiation effects , Half-Life , Hexanes/chemistry , Least-Squares Analysis , Photolysis , Polychlorinated Biphenyls/chemistry , Reproducibility of Results , Ultraviolet Rays
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