our group

proJects

Current projects

2014-2018 Role of tryptophan residues in the aggregation and fragmentation of peptides and proteins induced by peroxyl and carbon-centered radicals. FONDECYT 1141142 (Principal Investigator: Dr. Camilo López).

2016-2019 Influence of tryptophan and tyrosine residues in the activity of meat-derived peptides as free radical scavengers and inhibitors of the NFκB activation. FONDECYT 1160749. (Principal Investigator:
Dra. Eva Dorta).

Past projects

2014-2015 Study of the oxidative damage on myofibrillar proteins mediated by hydrosoluble peroxyl radicals: role of polyphenols obtained from peel and seed of mango (Mangifera Indica L.) as potential antioxidant compounds. FONDECYT nº 3140307

2013-2015 Acquisition of a UHPLC-MS / MS equipment to support interdisciplinary research in the Chemical and Pharmaceutical Sciences at the Faculty of Chemistry, Pontifical Catholic University of Chile. FONDEQUIP Project nº EQM130032.

2010-2013 Extending the use of pyrogallol red as probe in methodologies aimed to estimate the scavenging activity of beverages and foods towards nitrite, hypochlorous acid, chloramines and peroxyl radicals. FONDECYT nº 1100659.

2006-2009 Development and application of new methodologies to assess antioxidant capacity in aqueous and compartmentalized media.
FONDECYT nº 11060323.

SELECTED PAPERS

A novel and simple ORAC methodology based on the interaction of Pyrogallol red with peroxyl radicals.

C. López-Alarcón, E. Lissi* (2006). Free Radical Research. 40(9):979-985.

Oxidative damage of lysozyme and human serum albumin and their mixtures. A comparison of photosensitized and peroxyl radicals promoted processes.

A. Arenas, R. Vasquez, C. López-Alarcón, E. Lissi, E. Silva* (2011). The Protein Journal. 30(5):359-365.

Evaluating the antioxidant capacity of natural products: In vitro and cellular assays.

C. López-Alarcón, A. Denicola* (2013). Analytica Chimica Acta. 763(1): 1-10.

The role of protein-derived free radicals as intermediaries of oxidative processes.

C. López-Alarcón, A. Arenas, E. Lissi, E. Silva* (2014). Biomolecular Concepts. 5(2):119-130.

Chemical modification of lysozyme, glucose 6-phosphate dehydrogenase and bovine eye lens proteins induced by peroxyl radicals: role of oxidizable amino acid residues.

A. Arenas, C. López-Alarcón, M.J. Kogan, E. Lissi, M.J. Davies, E. Silva* (2013). Chemical Research in Toxicology. 26(1):67–77.

The ORAC (oxygen radical absorbance capacity) index does not reflect the capacity of antioxidants to trap peroxyl radicals.

E. Dorta, A. Aspée, E. Atala, H. Speisky, R. Bridi, E. Lissi, C. López-Alarcón* (Communication, 2015). RSC Advances. 5: 39899-39902.

Oxidation of free, peptide and protein tryptophan residues mediated by AAPH-derived free radicals: role of alkoxyl and peroxyl radicals.

E. Fuentes-Lemus, E. Dorta, E. Escobar, A. Aspee, E. Pino, M.L. Abasq, H. Speisky, E. Silva, E. Lissi, M.J. Davies, C.López-Alarcon* (2016). RSC Advances. 6, 57948–57955.

Use of the Oxygen Radical Absorbance Capacity (ORAC) assay to predict the capacity of mango (Mangifera indica L.) by-products to inhibit meat protein oxidation.

E. Dorta,* E.M. Rodríguez-Rodríguez, A. Jiménez-Quezada, E. Fuentes-Lemus, H. Speisky, E. Lissi, C. López-Alarcón (2017). Food Analytical Methods. 10, 2:330–338.

The peroxyl radical-induced oxidation of Escherichia coli FtsZ and its single tryptophan mutant (Y222W) modifies specific side-chains, generates protein cross-links and affects biological function.

E. Escobar-Álvarez, F. Leinisch, G. Araya, O. Monasterio, Lasse G. Lorentzen, E. Silva, M.J. Davies, C. López-Alarcón* (2017). Free Radical Biology and Medicine. 112: 60-68.

α- and β- casein aggregation induced by riboflavin-sensitized photo-oxidation occurs via di-tyrosine cross-links and is oxygen concentration dependent.

E. Fuentes-Lemus,  E.Silva,  F. Leinisch,  E. Dorta.  L.G. Lorentzen,  M.J. Davies,* C. López-Alarcón* (2018). Food Chemistry, in press.

COLLABORATIONS

National Collaborators

Prof. Alexis Aspee; Facultad de Química y Biología, Universidad de Santiago de Chile.

Prof. Eduardo Pino; Facultad de Química y Biología, Universidad de Santiago de Chile.

Prof. Felipe Ávila; Facultad de Nutrición, Universidad de Talca.

Prof. Octavio Monasterio; Facultad de Ciencias, Universidad de Chile.

Prof. Angélica Fierro; Facultad de Química, Pontificia Universidad Católica de Chile.

Prof. Mario Faúndez; Facultad de Química, Pontificia Universidad Católica de Chile.

International Collaborators

Prof. Ana Denicola; Facultad de Ciencias, Universidad de la República, Uruguay.

Prof. Michael Davies; Department of Biomedical Sciences, University of Copenhagen, Denmark.

Prof. Marie Laurence Abasq; Faculté du Pharmacie, Université de Rennes 1, France.

Prof. Benjamin Rojano; Universidad Nacional de Colombia, Sede Medellín, Colombia.

Dr. Juan Navarro; Hospital Universitario Nuestra Señora de La Candelaria, España.

Dra. Elena María Rodríguez Rodríguez; Universidad de La Laguna, España.

 

equipments

At present, we have chromatographic (HPLC and size exclusion), spectrophotometric (UV-vis and fluorescence microplate readers and conventional instruments), and electrophoretic (SDS-PAGE, western blotting with Trans-Blot Turbo) instruments. Besides, throughout a Fondequip project, we have access to a UPLC-chromatograph with mass detection (triple-quad). We hope, through the understanding of the basic phenomena of protein oxidation, to contribute to the scientific knowledge for the search of future solutions of different pathologies and food systems problems associated with oxidative processes on proteins. Our previous experience about the chemistry of free radicals and polyphenols allow us to address our current goals from a particular point of view. In future, we hope to go forward in a deep understanding of the oxidation of those proteins relevant to some central metabolic pathways of cells (for example those included in the oxidative phase of the pentose phosphate pathway) associated with the development of pathologies with high prevalence in Occidental populations. Additionally, we hope to understand and propose solutions for current problems of the food industry.

CONTACT

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In cells, tissues, and biological fluids, protein content is significantly higher than other bio-macromolecules, which would reflect their importance in biological environments. In fact, proteins play a relevant role in many biological functions highlighting those related to metabolic and structural processes. Amongst other factors, the high content of proteins favors reactions towards oxygen and nitrogen-derived reactive species leading to oxidative modifications on the protein structure. Such changes have been directly associated with the etiology of several human pathologies, amongst others, neurodegenerative and cardiovascular diseases, are the most studied. On the other hand, protein oxidation is also important in food systems. For example, food processing could trigger oxidative reactions altering the nutritional quality of foods and eventually generating oxidized (and deleterious) products.

Protein oxidation is a complex process involving multiple reaction pathways (see scheme) with the formation of several reactive intermediates, and products.

 

Our research group (Free Radicals and Protein Oxidation) aims to study, from a broad perspective, the chemistry behind protein oxidation. We hope to understand reaction mechanisms of such processes with a particular focus on the reactions involving tryptophan and tyrosine modifications leading to changes in the molecular mass of proteins (aggregates and fragments). To address this challenge, we work in collaboration with researchers in fields such as biochemistry, computing chemistry, photochemistry, physical chemistry, and biology. Our research has been funded by several Fondecyt grants.

 

 

Acknowledgements: This web page was supported by FONDECYT (grant n°1141142).

- Free Radicals and Protein Oxidation Group (FRPROT) -