Binding of V-IV to human transferrin: Potential relevance to anticancer activity of vanadocene dichloride

The action mechanism of vanadocene dichloride, Cp2VCl2 (CP = eta(5)-C5H5), has been investigated by interaction with human serum transferrin for its promising antitumor activities. Our results have shown that Cp2VCI2, binds to transferrin and form a new complex, and the calculated apparent association constant is 1.37 x 10(5) M-1 from the fluorescence quenching. Simultaneously, the variation of the secondary structure of transferrin occurs, most probably due to the coordination of the amino residues of protein with V-IV. It was evidenced that Cp is released free in solution after V-IV binding to transferrin by H-1 NMR measurements. These results have shown that Cp2VCl2, forms a complex with transferrin, which may provide a possible pathway in the transport and targeted delivery of the antitumor agent. (c) 2007 Elsevier Inc. All rights reserved.