The anticancer drug cisplatin (<i>cis</i>-Pt(NH<sub>3</sub>)<sub>2</sub>Cl<sub>2</sub>) results in cell death due primarily to its interaction with DNA, specifically at guanine residues.  The interaction of cisplatin and its analogs with proteins is a side reaction that could be responsible for toxicity and/or acquired resistance of the drug.  Also, platinum complexes may be useful as agents that cleave proteins and peptides regioselectively on the C-terminal side of methionine.  We are therefore characterizing the reaction of amino acids, primarily methionine, with bulky platinum complexes such as [Pt(Me<sub>4</sub>en)(D<sub>2</sub>O)<sub>2</sub>]<sup>2+</sup> [Me<sub>4</sub>en = N,N,N',N'-tetramethylethylenediamine] and [Pt(Et<sub>2</sub>en)(D<sub>2</sub>O)<sub>2</sub>]<sup>2+</sup> [Et<sub>2</sub>en = N,N-diethylethylenediamine]; the latter is non-C<sub>2</sub>-symmetrical and has bulk at only one nitrogen.  [Pt(Me<sub>4</sub>en)(D<sub>2</sub>O)<sub>2</sub>]<sup>2+</sup> reacts with methionine and N-acetylmethionine in a 1:1 molar ratio and forms chelates via the sulfur and nitrogen atoms for methionine and sulfur and oxygen atoms for N-acetylmethionine [Williams et al. <i>Inorganic Chemistry</i>, <b>2004</b>, <i>43</i>, 1190-1196].  One and two-dimensional NMR spectroscopy are being utilized to characterize these complexes.