A theoretical study of the binding of polychlorinated biphenyls (PCBs), dibenzodioxins, and dibenzofuran to human plasma prealbumin.

Binding energies to human plasma prealbumin using the energy minimization program AMBER are found for a series of polychlorinated biphenyls, dibenzodioxins, and dibenzofuran. Corrections for solvation free energies of the chlorinated analogues lead to estimates of the differential free energies of complex formation. These are compared in a number of cases to known experimental log (KPCB/Kref) values. The theory correctly separates strong, intermediate, and nonbinders. On the basis of calculations, 2,3,7,8-tetrachlorodibenzodioxin and 2,3,7,8-tetrachlorodibenzofuran are predicted to be strong binders, 3,3',5,5'-tetrachlorodiphenoquinone is predicted to be a weak binder, and octachlorodibenzodioxin is predicted to not bind at all. This theoretical model for prealbumin interactions may be of use in estimating the toxic potential of PCBs and related halogenated aromatic hydrocarbons of environmental importance.