Identification of Covalent Binding Sites of Phthalic Anhydride in Human Hemoglobin.

• Phthalic anhydride (PA) is a reactive low molecular weight compound used in the chemical industry. The exposure of PA may lead to work-related airway diseases such as rhinitis, chronic bronchitis, and asthma. The exposure gives rise to an increase in hapten-specific IgG antibodies in workers but with a low presence of specific IgE antibodies. In this study, the binding of PA to human hemoglobin (Hb) in vitro was investigated. Trypsin and Pronase E digestion, LC, LC/MS/MS, GC/MS analysis, and nanoelectrospray hybrid quadrupole time-of-flight MS were used to identify the adducted amino acids of the synthesized PA-Hb conjugates. In the conjugate with the molar ratio 1:0.1, a total of six adducted amino acids were identified. N-Terminal valine was found adducted in both the alpha- and the beta-chains as well as a total of four lysines, Val 1, Lys 16, and Lys 61 on the alpha-chain and Val 1, Lys 66, and Lys 144 on the beta-chain. Two types of lysine adducts were found, a phthalamide and a phthalimide. It was also found that PA differs in its binding site as compared to hexahydrophthalic anhydride. The result of this study suggests several interesting applications of biological monitoring.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Farmakologi och toxikologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Pharmacology and Toxicology (hsv//eng)

Publication and Content Type

art (subject category)

ref (subject category)