Formation of covalent adducts between compound 1 and MDMX.

<p><b>Panel a.</b> Mass spectrum arising from unmodified hMDMX (GST-tagged screening construct) showing unmodified mass of the protein. <b>Panel b.</b> Mass spectrum arising from treatment of 20 µM GST-hMDMX with 100 µM of compound <b>1</b> demonstrating multiple alkylation events. Note that 100 µM is well above the solubility limit of compound <b>1</b> and significant aggregation of compound exists. <b>Panel c.</b> Mass spectrum arising from treatment of 1 µM GST-hMDMX with 5 µM of compound <b>1</b> demonstrating no alkylation events. <b>Panel d.</b> Mass spectrum arising from unmodified hMDMX (untagged aa 23 to 111 construct) showing unmodified mass of the protein. <b>Panel e.</b> Mass spectrum arising from treatment of 20 µM hMDMX with 100 µM of compound <b>1</b> demonstrating partial alkylation. <b>Panel f.</b> Mass spectrum arising from treatment of 1 µM hMDMX with 5 µM of compound <b>1</b> demonstrating no alkylation.