Binding of perfluorinated fatty acids to serum proteins

Abstract

Abstract-Perfluorooctane sulfonic acid (PFOS) accumulates in the liver and blood of exposed organisms. The potential for these surfactant molecules to interfere with hormone/protein interactions in blood is of concern given the importance of these interactions. The PFOS binding to serum proteins was investigated by assessing its ability to displace a variety of steroid hormones from specific binding proteins in the serum of birds and fishes. Perfluorooctane sulfonic acid had only a weak ability to displace estrogen or testosterone from carp serum steroid binding proteins. Displacement of cortisone in avian sera occurred at relatively low PFOS concentrations. Corticosterone displacement potency increased with chain length, and sulfonic acids were more potent than carboxylic acids. The PFOS concentrations estimated to cause these effects were 320 M or greater, equivalent to serum concentrations greater than 160 mg/L. Using mass spectrometry and direct in vitro binding assays, PFOS was demonstrated to bind strongly to bovine serum albumin (BSA) in a 1:1 stoichiometric ratio. It appears that PFOS in serum is in general bound to albumins. Concentrations of PFOS required to saturate albumin would be in excess of 50 to 100 mg/L. Based on current environmental concentrations, it is unlikely that PFOS would cause displacement of hormones from serum proteins in wildlife.

Acute Enhancement of Synaptic Transmission and Chronic Inhibition of Synaptogenesis Induced by Perfluorooctane Sulfonate through Mediation of Voltage-Dependent Calcium Channel

“…However, involvement of other subtypes of calcium channels cannot be excluded, since PFOS-induced [Ca 2+ ]i increase was not completely blocked by nifedipine. As for the specific mechanism of action, Harada and co-workers (14) deduced that PFOS may directly activate calcium currents at specific lipid (25). PFOS has a sulfonic group attached to the perfluorinated chain, and PFOA has a carboxylic group.…”

Brain region distribution and patterns of bioaccumulative perfluoroalkyl carboxylates and sulfonates in East Greenland polar bears (Ursus maritimus)

“…This hypothesis has been supported by studies on free-ranging mammals, including polar bears, which reported no correlation of PFAA concentrations with extractable lipid levels in either liver or plasma samples [12][13][14]. The polar moiety of the PFSA and PFCA molecule preferentially binds with proteins over nonpolar molecules (e.g., free fatty acids), specifically fatty acid binding proteins, lipoproteins, and albumin, and is sequestered into protein-rich tissues such as liver and blood [15][16][17]. Very recently, Cassone et al [18] reported that chicken egg embryos injected with perfluorohexane sulfonate (PFHxS) and perfluorohexanoic acid (PFHxA) had greater accumulation in proteinrich compartments (i.e., yolk sac and liver).…”

“…Chain lengths for PFCAs of C 8 to C 15 and for PFSAs of C 6 , C 8 , and C 10 , as well as PFOSAs, were detected above the MLOQ in all brain compartments ( Table 2). All other PFASs were either below the detection limit, detected with low frequency, or detected near the detection limit (Supplemental Data, Table S3).…”

“…2), only a few compounds were correlated within an individual compartment. The PFCAs (C 13 -C 15 ) were strongly correlated in the pons/medulla (r ¼ 0.53-0.66), C 12 -C 14 PFCAs were strongly correlated in the temporal cortex (r ¼ 0.59-0.66), C 13 PFCA was strongly correlated in the frontal cortex (r ¼ 0.60), and C 14 -C 15 PFCAs were strongly correlated in the cerebellum (r ¼ 0.61 and 0.60, respectively; Fig. 2).…”

Study on the binding interaction between perfluoroalkyl acids and DNA

“…The tested PFAAs have the ability to compete and displace fatty acids from the protein, and consequently change the distribution between free and bound fatty acids in plasma (Chen and Guo 2009). PFOS was demonstrated to bind strongly to bovine serum albumin (BSA) (Jones et al 2003). Noncovalent interactions of PFOS with BSA alter its secondary conformation, and such changes inhibit the physiological function of BSA to transport vitamin B 2 (Wu et al 2009).…”