Tristetraprolin (TTP) is a non-classical zinc finger proteins found in man and most other mammals. TTP contains three cysteines and one histidine (Cys3His) that bind to metal ions. During inflammation, TTP regulates the expression of cytokines including tumor necrosis factor a (TNF-a) at mRNA level. In the regulation of cytokines, TTP binds to AU-rich sequence elements (AREs) located on the cytokines' mRNA. Upon binding the TTP/ mRNA complex is degraded by exosomes. It has been established that coordination of zinc ion to the Cys3His sequence of TTP ion is required for TTP to bind with RNA. To evaluate the role of metal ions in TTP function, TTP-2D, a two finger domain was expressed and purified. 0.1 mg of TTP-2D was collected and determined to be over 95% pure by SDS-PAGE and HPLC analysis. Metal binding tests by diTargiani and coworkers provided data that could be fit to yield an upper limit dissociation constant Kd of 3.3 � 10-6 M for cobalt (II) binding and 6.2 x 10-11 M for zinc (II).