Binding of [Cr(phen)3]3+ to transferrin at extracellular and endosomal pHs: Potential application in photodynamic therapy

PABLO F. GARCÍA; J. TONEATTO; M. JAZMÍN SILVERO,; ARGÜELLO, GERARDO ANÍBAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2014 vol. 1840 p. 2695 - 2695

ackground: Transferrin is an iron-binding blood plasma glycoprotein that controls the level of free iron in biological fluids. This protein has been deeply studied in the past few years because of its potential use as a strategy of drug targeting to tumor tissues. Chromium complex, [Cr(phen)3]3+ (phen = 1,10-phenanthroline), has been proposed as photosensitizers for photodynamic therapy (PDT). Thus, we analyzed the binding of chromium complex, [Cr(phen)3]3+, to transferrin for a potential delivery of this diimine complex to tumor cells for PDT. Methods: The interaction between [Cr(phen)3]3+ and holotransferrin (holoTf) was studied by fluorescence quenching technique, circular dichroism (CD) and ultraviolet (UV)?visible spectroscopy. Results: [Cr(phen)3]3+ binds strongly to holoTfwith a binding constant around 105M−1, that depends on the pH. The thermodynamic parameters indicated that hydrophobic interactions played amajor role in the binding processes. The CD studies sh