Homogeneous and heterogeneous oxidation of BSA photosensitized by Rose Bengal

ARGAÑARAZ, NATALIA M.; ESPECHE TURBAY, B; REY, VALENTINA; BORSARELLI, CLAUDIO D.

Córdoba

Encuentro; XI Encuentro Latinoamericano de Fotoquímica y Fotobiologia; 2012

Proteins like other biological macromolecules may be targets of action of reactive oxygen species (ROS). The oxidation of these substrates produces changes of the functionality and / or alterations of the structure causing changes at the physiological level. As a result, the characterization of protein oxidative damage both 1O2 or other ROS, by using model systems for evaluating in vitro the damage occurring in biological media, it is necessary. In the above function, the objective of this work was to study the oxidation of bovine serum albumin (BSA) by 1O2 generated by photosensitization of Rose Bengal dye xanténico (RB) in homogeneous and heterogeneous media. This would assess the efficiency of photo-oxidative process in the different media. In this work we have focused on analyzing the photo-oxidation that occurs in the adduct formed by BSA with RB (homogeneous media), and in heterogeneous media, wherein the dye is adsorbed on ion exchange resins. The characterization of the oxidation photoinduced BSA in function of different molar ratios dye / protein was evaluated using various spectroscopic techniques UV-Vis absorption and fluorescence, as well as analytical and biochemical techniques. The observed changes in absorbance and fluorescence spectra, as well as biochemical studies show that the photosensitized oxidation degree of BSA in solution is greater than that observed in heterogeneous media. Thus we can conclude that the processes of photosensitization in vitro are an appropriate methodology for studying protein oxidation and interpret the changes of oxidative stress on them carried out in biological media.