Impact of Carbon Chain Length on Binding of Perfluoroalkyl Acids to Bovine Serum Albumin Determined by Spectroscopic Methods

• Published in: Journal of agricultural and food chemistry Vol. 58; no. 9; pp. 5561 - 5567
• Main Authors: Qin, Pengfei, Liu, Rutao, Pan, Xingren, Fang, Xiaoyan, Mou, Yue
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 12.05.2010
• Subjects: Acids - chemistry; amino acid composition; Bertholletia excelsa; binding properties; biochemical compounds; Biological and medical sciences; bovine serum albumin; Brazil nuts; carbon; Carbon - chemistry; carbon chain length; Circular Dichroism; Environmental Chemistry; fluorescence; fluorescence quenching; Fluorocarbons - chemistry; food analysis; food composition; Food industries; Fundamental and applied biological sciences. Psychology; glycoproteins; Hydrogen Bonding; length; Milk and cheese industries. Ice creams; perfluoroalkyl acids; pollutants; pollution; purification; Serum Albumin, Bovine - chemistry; Spectrometry, Fluorescence; spectroscopy; storage proteins; toxicity; Perfluoroalkyl acids (PFAAs); toxicological evaluation; bovine serum albumin (BSA); fluorescence; Binding; Evaluation; Bovine; Chain length; Fluorescence; Serum albumin; Method; Carbon; Globular protein; Milk protein; Vertebrata; Mammalia; Acids; Artiodactyla; Whey protein; Ungulata
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf100412q

Perfluoroalkyl acids (PFAAs), an emerging class of globally environmental contaminants, pose a great threat to humans with wide exposure from food and other potential sources. To evaluate the toxicity of PFAAs at the protein level, the effects of three PFAAs on bovine serum albumin (BSA) were characterized by fluorescence spectroscopy, synchronous fluorescence spectroscopy, and circular dichroism (CD). On the basis of the fluorescence spectra and CD data, we concluded that perfluoropentanoic acid (PFPA) had little effect on BSA. However, perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) exhibited remarkable fluorescence quenching, which was attributed to the formation of a moderately strong complex. The enthalpy change (ΔH) and entropy change (ΔS) indicated that van der Waals forces and hydrogen bonds were the dominant intermolecular forces in the binding of PFAAs to BSA. Furthermore, the BSA conformation was slightly altered in the presence of PFOA and PFDA, with a reduction of α helix. These results indicated that PFAAs indeed impact the conformation of BSA, and PFAAs with longer carbon chains were more toxic, especially at lower concentrations.