title: Reaction monitoring of platinum(II) complex--5'-guanosine monophosphate adduct formation by ion exchange liquid chromatography/electrospray ionization mass spectrometry.
abstract: Cisplatin and four structurally related platinum(II) complexes were incubated with guanosine 5'-monophosphate (5'-GMP) in water at 37 degrees C. The adduct formation reactions were monitored with cation- and anion-exchange liquid chromatography/electrospray ionization mass spectrometry. In addition to mono- and bis-adducts of guanosine 5'-monophosphate with the platinum(II) complexes, other molecular species, presumably with a binuclear structure (two platinum(II) centres), were detected in the reaction mixtures, which have not been reported previously, indicating an unexpected complexity of adduct formation. Anion-exchange chromatography revealed the presence of isomers of two complexes which presumably result from the restricted rotation at the platinum-- N-7 (5'-GMP) bonds. All reaction products were characterized in both the positive and negative ion modes. Furthermore, preliminary kinetics and half-times of complex formation were investigated for cisplatin and two other platinum(II) complexes, monitoring the relative concentrations of free 5'-GMP and of mono- and bis-GMP adducts as a function of time (250 h) using an internal standard protocol with thymidine 5'-monophosphate.
authors.affiliation: Institute of Analytical Chemistry, University of Vienna, Währinger Str. 38, A-1090 Vienna, Austria. pezo@olivin.univie.ac.at
authors.forename: P
authors.initials: P
authors.lastname: Zöllner
authors.forename: A
authors.initials: A
authors.lastname: Zenker
authors.forename: M
authors.initials: M
authors.lastname: Galanski
authors.forename: B K
authors.initials: BK
authors.lastname: Keppler
authors.forename: W
authors.initials: W
authors.lastname: Lindner