We have reacted [Pt(Me4en)(D2O)2]2+ [Me4En=N,N,N’N’-tetramethylethylenediamine] with Selenomethionine (SeMet), Methionine (Met), and Methylselenocysteine (MeSeCys). When MeSeCys was reacted with [Pt(Me4en)(D2O)2]2+, we observed both stereoisomers of Se,N chelates, as well as [Pt(Me4en)(MeSeCys)Cl]+ from 1H NMR Spectroscopy; the latter formed due to the presence of Cl- in the solution. Both isomers of the chelate seemed to form proportionally to one another, not favoring a specific stereoisomer. Eventually the [Pt(Me4en)(MeSeCys)Cl]+ products became Se,N chelates. We incubated SeMet with NaCl for 30 minutes and then mixed with [Pt(Me4en)(D2O)2]2+; we saw equal amounts of the [Pt(Me4en)(SeMet)Cl]+ isomers along with a specific stereoisomer of the Se,N chelate forming first (R chirality), then approximately two hours later the (S) chirality formed. Previously, Met and [Pt(Me4En(D2O)2]2+ have been studied by prior students and there were no chiralities favored in the reaction. There were S,N chelates formed, but no specific isomer favored over another. We obtained equal amounts of SeMet, Met and [Pt(Me4en)(D2O)2]2+ and mixed the solutions together to see which amino acid would platinate first, either SeMet or Met. The NMR spectra we observed showed that SeMet attached first to [Pt(Me4en)(D2O)2]2+, with the (R) chelate forming first, then the (S) chelate. Met was slow to react, and we saw both chelates form at approximately equal rates.
Advisor(s) or Committee Chair
Dr. Kevin Williams
Biochemistry | Chemistry | Other Biochemistry, Biophysics, and Structural Biology
Robey, Stephanie, "Reactions With Platinum (ll) Complexes And Selenium-Containing Amino Acids" (2011). Honors College Capstone Experience/Thesis Projects. Paper 338.