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Identification of protein targets for mycophenolic acid acyl glucuronide in rat liver and colon tissue
Author(s) -
Shipkova Maria,
Beck Hermann,
Voland Antje,
Armstrong Victor W.,
Gröne HermannJosef,
Oellerich Michael,
Wieland Eberhard
Publication year - 2004
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200300836
Subject(s) - chemistry , protein disulfide isomerase , biochemistry , gel electrophoresis , mycophenolate , biliverdin reductase , microbiology and biotechnology , enzyme , biology , transplantation , medicine , heme , heme oxygenase , surgery
Covalent binding of acyl glucuronides to proteins is considered an initiating event for the organ toxicity of drugs containing a carboxylic acid group. An acyl glucuronide (AcMPAG) of the immunosuppressant mycophenolic acid was described and shown to form covalent adducts with plasma albumin in vivo . The aim of the present investigation was to identify AcMPAG target proteins in the liver and colon of rats treated with mycophenolate mofetil, which may contribute to a better understanding of the mechanisms responsible for the development of side effects during therapy with this drug. Mycophenolate mofetil was administered per os in to Wistar rats (40 mg/kg/day) over 21 days. Proteins in liver and colon homogenates were separated by two‐dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis. AcMPAG labeled protein spots were detected by Western blotting. After in‐gel tryptic digestion of the protein spots from parallel gels ( n = 2), peptides were characterized by matrix‐assisted laser desorption/ionization‐time of flight‐mass spectrometry. Data base searching identified AcMPAG target proteins. Tryptic peptides with sufficient signal intensities were subjected to post‐source decay analysis. Three proteins in the liver (ATPase/ATP synthase (alpha and beta subunits), protein disulfide isomerase A3 and selenium binding protein) and one protein in the colon (selenium binding protein) were identified as targets for AcMPAG. ATPase/ATP synthase and protein disulfide isomerase are essential proteins involved in the control of the energy and redox state of the cells, whereas the physiological role of selenium binding protein is not fully understood. This study shows for the first time the formation of adducts between tissue proteins and AcMPAG. Whether this chemical modification is associated with compromised protein function and drug toxicity remains to be investigated.