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Sulfation of Lower Chlorinated Polychlorinated Biphenyls Increases Their Affinity for the Major Drug-Binding Sites of Human Serum Albumin
Journal article   Open access   Peer reviewed

Sulfation of Lower Chlorinated Polychlorinated Biphenyls Increases Their Affinity for the Major Drug-Binding Sites of Human Serum Albumin

Eric A Rodriguez, Xueshu Li, Hans-Joachim Lehmler, Larry W Robertson and Michael W Duffel
Environmental science & technology, Vol.50(10), pp.5320-5327
05/17/2016
DOI: 10.1021/acs.est.6b00484
PMCID: PMC4883002
PMID: 27116425
url
http://doi.org/10.1021/acs.est.6b00484View
Open Access

Abstract

The disposition of toxicants is often affected by their binding to serum proteins, of which the most abundant in humans is serum albumin (HSA). There is increasing interest in the toxicities of environmentally persistent polychlorinated biphenyls (PCBs) with lower numbers of chlorine atoms (LC-PCBs) due to their presence in both indoor and outdoor air. PCB sulfates derived from metabolic hydroxylation and sulfation of LC-PCBs have been implicated in endocrine disruption due to high affinity-binding to the thyroxine-carrying protein, transthyretin. Interactions of these sulfated metabolites of LC-PCBs with HSA, however, have not been previously explored. We have now determined the relative HSA-binding affinities for a group of LC-PCBs and their hydroxylated and sulfated derivatives by selective displacement of the fluorescent probes 5-dimethylamino-1-naphthalenesulfonamide and dansyl-l-proline from the two major drug-binding sites on HSA (previously designated as Site I and Site II). Values for half-maximal displacement of the probes indicated that the relative binding affinities were generally PCB sulfate ≥ OH-PCB > PCB, although this affinity was site- and congener-selective. Moreover, specificity for Site II increased as the numbers of chlorine atoms increased. Thus, hydroxylation and sulfation of LC-PCBs result in selective interactions with HSA which may affect their overall retention and toxicity.
Sulfates - metabolism Hydroxylation Prealbumin - metabolism Proline - analogs & derivatives Humans Thyroxine - metabolism Halogenation Polychlorinated Biphenyls - metabolism Binding Sites Dansyl Compounds Physical Phenomena Serum Albumin - metabolism ISRP Project 1 2015-2020 ISRP Project 3 2015-2020 Synthesis Core

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