Browsing by Author "Aspee, Alexis"
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- ItemAggregation of alpha- and beta- caseins induced by peroxyl radicals involves secondary reactions of carbonyl compounds as well as di-tyrosine and di-tryptophan formation(2018) Fuentes Lemus, Eduardo Felipe; Silva, Eduardo; Barrias, Pablo; Aspee, Alexis; Escobar Álvarez, Elizabeth; Lorentzen, Lasse G.; Carroll, Luke; Leinisch, Fabian; Davies, Michael J.; López Alarcón, Camilo Ignacio
- ItemAntioxidant capacity of phenolic compounds in acidic medium : a pyrogallol red-based ORAC (oxygen radical absorbance capacity) assay(2013) Atala, Elias; Aspee, Alexis; Speisky, Hernán; Lissi, Eduardo; López Alarcón, Camilo Ignacio
- ItemAntioxidant reactivity toward nitroxide probes anchored into human serum albumin. A new model for studying antioxidant repairing capacity of protein radicals(2009) Aspee, Alexis; Orrego, Alejandra; Alarcón Abarzúa, Emilio Isaac; López Alarcón, Camilo Ignacio; Poblete, Horacio; Gonzalez-Nilo, Danilo
- ItemAtypical antioxidant activity of non-phenolic amino-coumarins(2018) Zuniga-Nunez, Daniel; Barrias, Pablo; Cardenas-Jiron, Gloria; Soledad Ureta-Zanartu, M.; López Alarcón, Camilo Ignacio; Moran Vieyra, F. Eduardo; Borsarelli, Claudio D.; Alarcon, Emilio I.; Aspee, Alexis
- 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.
- ItemCompetitive kinetics in free radical reactions of cinnamic acid derivatives. Influence of phenoxyl radicals reactions(2007) López Alarcón, Camilo Ignacio; Aspee, Alexis; Lissi, Eduardo
- ItemDistribution and reactivity of gallates toward galvinoxyl radicals in SDS micellar solutions - Effect of the alkyl chain length(2011) Bridi, Raquel; Aliaga, Carolina; Aspee, Alexis; Abuin, Elsa; Lissi, Eduardo
- ItemElectrochemical and Spectroscopic Study of Pyranine Fluorescent Probe: Role of Intermediates in Pyranine Oxidation(2011) Velasquez, Gabriela; Ureta-Zanartu, M. Soledad; López Alarcón, Camilo Ignacio; Aspee, Alexis
- ItemFree radical scavenging capacity of hydroxycinnamic acids and related compounds(2006) Pino, Eduardo; Campos, Ana M.; López Alarcón, Camilo Ignacio; Aspee, Alexis; Lissi, Eduardo
- 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.
- ItemInfluence of the Target Molecule on the ORAC Index(2012) López Alarcón, Camilo Ignacio; Aspee, Alexis; Lissi, Eduardo
- ItemInteraction and reactivity of urocanic acid towards peroxyl radicals(2005) López Alarcón, Camilo Ignacio; Aspee, Alexis; Henriquez, C.; Campos, A.M.; Lissi, E.A.
- ItemPhotobehavior of merocyanine 540 bound to human serum albumin(2010) Alarcón Abarzúa, Emilio Isaac; Aspee, Alexis; González Bejar, María; EdwardsM., Ana M; Lissi, E. A.; Scaiano, J. C.
- 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.
- ItemReactivity of hydroxynaphthalene towards peroxyl radicals(2006) Pino, Eduardo; Aspee, Alexis; López Alarcón, Camilo Ignacio; Lissi, E.
- ItemRelevance of secondary processes in ORAC values obtained employing pyrogallol red as target molecule(2009) López Alarcón, Camilo Ignacio; Aspee, Alexis; Lissi, E. A.
- ItemRiboflavin-induced Type 1 photo-oxidation of tryptophan using a high intensity 365 nm light emitting diode(2019) Silva, Eduardo; Barrias, Pablo; Fuentes Lemus, Eduardo Felipe; Tirapegui, Cristian; Aspee, Alexis; Carroll, Luke; Davies, Michael J.; López Alarcón, Camilo Ignacio
- ItemTime-resolved fluorescence and anisotropy-sensitive 1,2-dimyristoyl-sn-glycero-3-(7-aminocoumarin) phosphoetanolamide probe for studying membrane lipid domains(ELSEVIER SCI LTD, 2023) Zúñiga Núñez, Daniel; Mura, Francisco; Mariño-Ocampo, Nory; Briones-Rebolledo, Patricio; Poblete, Horacio; Mallet, Jean-Maurice; Fuentealba Patino, Denis Alberto; Aspee, AlexisA fluorescent probe C-DMPE was synthesised to monitor interfacial membrane properties by conjugating coumarin-343 and 1,2-dimyristoyl-sn-glycero-3-phosphorylethanolamine (DMPE), anchoring the 7-aminocou-marin moiety close to the phospholipid polar head at the membrane interface. Large unilamellar vesicles (LUV) of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC), of 1,2-dioleyl-sn-glycero-3-phosphatidyl-choline (DOPC) and cholesterol were employed as a model of lipid bilayer. Time-resolved fluorescence developed an emissive Internal Charge Transfer excited state with a long fluorescence lifetime (T1), a Locally Excited state with an intermediate fluorescence lifetime (T2), and a short lifetime (T3) associated with an intermolecular quenching by interaction with a phosphate group of neighbour phospholipids, as is clearly shown by molecular dynamics simulations. Shorter values of fluorescence lifetimes T1 and T3 were observed in DOPC with respect to DPPC, responding to a more fluid membrane with more significant water accessibility in DOPC than DPPC. However, in DPPC:DOPC vesicles, these fluorescence lifetimes are even shorter, allowing to be attributed to favourable sensing of boundary limit lipid domains. In similitude, time-resolved anisotropy showed shorter rotational correlation times phi 1, in DPPC: DOPC vesicles than in DOPC associated with a faster internal rotational movement of the 7-aminocoumarin group in domains than in fluid a DOPC membrane. In addition, shorter rotational correlation times, (P2, were also observed in DPPC:DOPC vesicles compared to DPPC, suggesting a faster lateral diffusion of the probe in the presence of domains.