Laura MacManus-Spencer - Strong associations of short-chain perfluoroalkyl acids with serum albumin and investigation of binding mechanisms.

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  Publication Details (including relevant citation   information): Bischel, Heather N., MacManus-Spencer,   Laura A., Zhang, Chaojie, Luthy, Richard G., Environ.   Toxicol. Chem., 2011, 30 (11), pp   2423-2430

  Abstract: Interactions of perfluoroalkyl acids   (PFAAs) with tissue and serum proteins likely contribute to their   tissue distribution and bioaccumulation patterns. Protein-water   distribution coeffs. (KPW) based on ligand assocns. with bovine   serum albumin (BSA) as a model protein were recently proposed as   biol. relevant parameters to describe the environmental behavior   of PFAAs, yet empirical data on such protein binding behavior are   limited. In the present study, assocns. of perfluoroalkyl   carboxylates (PFCAs) with two to 12 carbons (C2-C12) and   perfluoroalkyl sulfonates with four to eight carbons (C4, C6, and   C8) with BSA are evaluated at low PFAA:albumin mole ratios and   various soln. conditions using equil. dialysis, nanoelectrospray   ionization mass spectrometry, and fluorescence spectroscopy. Log   KPW values for C4 to C12 PFAAs range from 3.3 to 4.3. Affinity   for BSA increases with PFAA hydrophobicity but decreases from the   C8 to C12 PFCAs, likely due to steric hindrances assocd. with   longer and more rigid perfluoroalkyl chains. The C4-sulfonate   exhibits increased affinity relative to the equiv. chain-length   PFCA. Fluorescence titrns. support evidence that an obsd.   dependence of PFAA-BSA binding on pH is attributable to   conformational changes in the protein. Assocn. consts. detd. for   perfluorobutanesulfonate and perfluoropentanoate with BSA are on   the order of those for long-chain PFAAs (Ka∼106/M), suggesting   that physiol. implications of strong binding to albumin may be   important for short-chain PFAAs. [on SciFinder(R)]

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