title: Identification of modification sites on human serum albumin and human hemoglobin adducts with houttuynin using liquid chromatography coupled with mass spectrometry.
abstract: Houttuynin, a β-keto aldehyde compound, is the major active ingredient in herba houttuyniae injection. The injection was once used as an anti-inflammatory drug associated with occasional serious hypersensitivity reactions in the clinic, which were proposed to be related to the formation of protein adducts. N(α) -Boc-lysine, FEEM and IVTNTT were used as model amino acids or peptides containing one nucleophilic residue to investigate adduct types by liquid chromatography coupled with ion trap mass spectrometry (LC/MS(n) ) and high-resolution quadrupole time-of-flight mass spectrometry (Q-TOF MS). These adducts were respectively characterized as Schiff bases formed by 1:1 reaction of houttuynin with lysine or N-terminal residue and pyridinium adducts by 2:1 reaction. LC/MS(n) analysis of trypsin digests of HSA/Hb incubations with houttuynin revealed that houttuynin-modified HSA adducts were formed mainly at N-terminal amino acid and lysine residues, specifically at Lys-212, Lys-414 and Lys-525 for Schiff base adducts, and at Lys-414 and Lys-432 for pyridinium adducts, and houttuynin adducted more readily with N-terminal valine of the α- and β-chains in Hb and lysine amine (Lys-62) of the β-chain for Schiff base adducts. The results showed the direct modification of houttuynin to HSA/Hb in vitro, which was speculated to be responsible for the adverse reactions induced by houttuyniae injection.
authors.affiliation: Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
authors.forename: Zhipeng
authors.initials: Z
authors.lastname: Deng
authors.forename: Dafang
authors.initials: D
authors.lastname: Zhong
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Chen
mesh_terms: D000447:Aldehydes / Q000737:chemistry* / Q000378:metabolism; D000595:Amino Acid Sequence; D002853:Chromatography, Liquid / Q000379:methods*; D006454:Hemoglobins / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008239:Lysine / Q000031:analogs & derivatives; D013058:Mass Spectrometry / Q000379:methods*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism; D013431:Sulfates / Q000737:chemistry
chemical_list: D000447:Aldehydes; D006454:Hemoglobins; D010446:Peptide Fragments; D012709:Serum Albumin; D013431:Sulfates; C012036:sodium sulfate; C023969:decanoyl acetaldehyde; D008239:Lysine