Advances on the interaction of polypyridyl Cr(III) complexes with transporting proteins and its potential relevance in photodynamic therapy

J. TONEATTO; P. F. GARCIA; G. A. ARGÜELLO

ELSEVIER SCIENCE INC

Lugar: Columbia; Año: 2011 vol. 105 p. 1299 - 1299

he present study reports a detailed investigation into the interaction of [Cr(phen)2(dppz)]3+ and [Cr(phen)3]3+ with transferrin, the key protein for the transport of Fe3+ in blood plasma; its cycle holds promise as an attractive system for strategies of drug targeting to tumor tissues. This can allow us to understand further the role of both complexes as sensitizers in photodynamic therapy (PDT). Chromium(III) complexes, [Cr(phen)2(dppz)]3+ and [Cr(phen)3]3+, (phen=1,10-phenanthroline and dppz=dipyridophenazine), where dppz is a planar bidentate ligand with an extended π system, have been found to bind strongly with apotransferrin (apoTf) with an intrinsic binding constant, Kb, of (1.8 ±0.3) × 10 5 M−1 and (1.1±0.1) × 10 5 M−1 at 299 K, for apoTf–[Cr(phen)2(dppz)]3+ and apoTf–[Cr(phen)3] 3+ , respectively. The interactions of apoTf with the different Cr(III) complexes were assessed employing UV–visible absorption, fluorescence and circular dichroism spectro