Browsing by Author "Lissi, Eduardo A."
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- ItemChemiluminescence associated with singlet oxygen reactions with amino acids, peptides and proteins(WILEY, 2007) Alarcon, Emilio; Henriquez, Carola; Aspee, Alexis; Lissi, Eduardo A.Low level chemiluminescence (CL) is observed after protein oxidation mediated by singlet oxygen produced in Rose Bengal (RB) irradiation. This CL lasts for several minutes after the end of the photolysis. In this work, the mechanism of the process was assessed from the spectral characteristics of the CL and the effect of antioxidants (Trolox or ascorbate), Ebselen (a compound with peroxidase-like activity), azide (a singlet oxygen scavenger) and D2O, added prior to or after RB irradiation. It is concluded that most of the light emission is due to formation of excited states generated in the decomposition of peroxides and/or hydroperoxides accumulated during the photolysis. Experiments carried out in the presence of several amino acids (Cys, Met, His, Tyr and Trp) and di- and tripeptides suggest that peroxides (and/or hydroperoxides) of Trp residues are mainly responsible for the CL observed after singlet oxygen-mediated protein oxidation. The much weaker CL observed after the oxidation of proteins without Trp residues supports this conclusion. A comparison of the results obtained employing free Trp, Ala-Trp and Trp-Ala dipeptides, Ala-Trp-Ala tripeptide and Trp-containing proteins supports the conclusion that blocking the amino group of the Trp moiety strongly increases the efficiency of the chemilummescent process, producing approximate to 2.5x10(-8) photons per oxidized Trp group in Alla-Trp. A mechanism comprising two chemiluminescent oxidation pathways of Trp residues is proposed to explain the results.
- ItemGeneration, spectroscopic characterization by EPR, and decay of a pyranine-derived radical(2007) Aliaga, Carolina; Arenas Lissi, Andrea Beatriz; Aspee, Alexis; López Alarcón, Camilo Ignacio; Lissi, Eduardo A.
- ItemPeroxynitrite oxidizes erythrocyte membrane band 3 protein and diminishes its anion transport capacity(2007) Celedon, Gloria; Gonzalez, Gustavo; Pino, Jose; Lissi, Eduardo A.We describe an altered membrane band 3 protein-mediated anion transport in erythrocytes exposed to peroxynitrite, and relate the loss of anion transport to cell damage and to band 3 oxidative modifications. We found that peroxynitrite down-regulate anion transport in a dose dependent relation (100-300 mu moles/1). Hemoglobin oxidation was found at all peroxynitrite concentrations studied. A dose-dependent band 3 protein crosslinking and tyrosine nitration were also observed. Band 3 protein modifications were concomitant with a decrease in transport activity. (-)-Epicatechin avoids band 3 protein nitration but barely affects its transport capacity, suggesting that both processes are unrelated. N-acetyl cysteine partially reverted the loss of band 3 transport capacity. It is concluded that peroxynitrite promotes a decrease in anion transport that is partially due to the reversible oxidation of band 3 cysteine residues. Additionally, band 3 tyrosine nitration seems not to be relevant for the loss of its anion transport capacity.
- ItemPhotophysics and photochemistry of dyes bound to human serum albumin are determined by the dye localization(2010) Alarcón Abarzúa, Emilio Isaac; EdwardsM., Ana M; Aspee, Alexis; Moran Vieyra, Faustino Eduardo; Borsarelli, Claudio D.; Lissi, Eduardo A.; González Nilo, Fernando Danilo; Poblete, Horacio; Scaiano, J. C.
- ItemPhotophysics and photochemistry of rose bengal bound to human serum albumin(2009) Alarcón Abarzúa, Emilio Isaac; EdwardsM., Ana M; Aspee, Alexis; Borsarelli, Claudio D.; Lissi, Eduardo A.
- ItemPhotophysics and photochemistry of zinc phthalocyanine bovine serum albumin adducts(2009) Alarcón Abarzúa, Emilio Isaac; EdwardsM., Ana M; García Torres, Angélica María; Muñoz Figueroa, Marcelo Alejandro; Aspee, Alexis; Borsarelli, Claudio D.; Lissi, Eduardo A.