Journal article
Physicochemical properties of hydroxylated polychlorinated biphenyls aid in predicting their interactions with rat sulfotransferase 1A1 (rSULT1A1)
Chemico-biological interactions, Vol.189(3), pp.153-160
2011
DOI: 10.1016/j.cbi.2010.11.009
PMCID: PMC3032042
PMID: 21130751
Abstract
Hydroxylated metabolites of polychlorinated biphenyls (OHPCBs) interact with rat sulfotransferase 1A1 (rSULT1A1) as substrates and inhibitors. Previous studies have shown that there are complex and incompletely understood structure–activity relationships governing the interaction of rSULT1A1 with these molecules. Furthermore, modification of the enzyme with glutathione disulfide (GSSG) results in the conversion of some OHPCBs from inhibitors to substrates. We have now examined estimated values for the acid-dissociation constant (
K
a) and the octanol–water distribution coefficient (
D), as well as experimentally determined dissociation constants for enzyme complexes, to assist in the prediction of interactions of OHPCBs with rSULT1A1. Under reducing conditions, initial velocities for rSULT1A1-catalyzed sulfation exhibited a positive correlation with p
K
a and a negative correlation with log
D of the OHPCBs. IC
50 values of inhibitory OHPCBs decreased with decreasing p
K
a values for both the glutathione (GSH)-pretreated and GSSG-pretreated forms of rSULT1A1. Comparison of GSH- and GSSG-pretreated forms of rSULT1A1 with respect to binding of OHPCB in the presence and absence of adenosine 3′,5′-diphosphate (PAP) revealed that the dissociation constants with the two redox states of the enzyme were similar for each OHPCB. Thus, p
K
a and log
D values are useful in predicting the binding of OHPCBs to the two redox forms of rSULT1A1 as well as the rates of sulfation of those OHPCBs that are substrates. However, the differences in substrate specificity for OHPCBs that are seen with changes in redox status of the enzyme are not directly related to specific structural effects of individual OHPCBs within inhibitory enzyme–PAP–OHPCB complexes.
Details
- Title: Subtitle
- Physicochemical properties of hydroxylated polychlorinated biphenyls aid in predicting their interactions with rat sulfotransferase 1A1 (rSULT1A1)
- Creators
- Yungang Liu - Division of Medicinal and Natural Products Chemistry, College of Pharmacy, University of Iowa, 115 So. Grand Avenue, Iowa City, IA 52242-1112, United StatesHans-Joachim Lehmler - Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242, United StatesLarry W Robertson - Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242, United StatesMichael W Duffel - Division of Medicinal and Natural Products Chemistry, College of Pharmacy, University of Iowa, 115 So. Grand Avenue, Iowa City, IA 52242-1112, United States
- Resource Type
- Journal article
- Publication Details
- Chemico-biological interactions, Vol.189(3), pp.153-160
- DOI
- 10.1016/j.cbi.2010.11.009
- PMID
- 21130751
- PMCID
- PMC3032042
- NLM abbreviation
- Chem Biol Interact
- ISSN
- 0009-2797
- eISSN
- 1872-7786
- Publisher
- Elsevier Ireland Ltd
- Language
- English
- Date published
- 2011
- Academic Unit
- Occupational and Environmental Health; Iowa Neuroscience Institute; Pharmaceutical Sciences and Experimental Therapeutics; Iowa Superfund Research Program; Medicinal and Natural Products Chemistry
- Record Identifier
- 9984000926202771
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