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Abstract No.: MoP-230
Session: Proteomics: General
Presentation date: Mon, Aug 28, 2006
Presentation time: 14:30 – 16:00

Discrimination of Close-related Fish Species by LC-MS/MS Using the Selected Ion Reaction Monitoring (SIR) Scanning Mode

Monica Carrera Mourino1, Carmen Pineiro Gonzalez1, Lorena Barros Tajes1, Benito Canas Montalvo2, Jose Manuel Gallardo Abuin1

1 Instituto De Investigaciones Marinas IIM-CSIC, Vigo, Spain
2 Dpto. Quimica Analitica, Facultad De Quimica, Universidad Complutense De Madrid, Madrid, Spain

Correspondence address: Monica Carrera Mourino, Instituto De Investigaciones Marinas, CSIC, Eduardo Cabello 6, Vigo, Pontevedra, 36208 Spain.

Keywords: Biomarkers; Mass Spectrometry; Proteomic; Selected Reaction Monitoring.

Novel aspect: We considered that this is a novel work where the power of mass spectrometry is applied to the authentication of species very closely in seafood products.

 

Due to the constant demand by the consumers in to know the quality and the origin of seafood products and to the news commercial regulations imposed by many countries all over the world, important efforts in our laboratory have been focused on the application of mass spectrometry for the identification of close-related fish species.

In this sense we have applied mass spectrometry, to achieve the differential characterization of all the different commercial species belonging to the Family Merlucciidae. Thus, we have characterized a number of specie-specific peptides as possible biomarkers for these species, whose proteomes are poorly described in the protein databases. For the characterization of these specific peptides, we have compared the peptide maps generated by MALDI-TOF mass spectrometry from 2-DE spots corresponding to different paravlbumin isoforms. From the technological point of view, parvalbumins can be defined as potential seafood authenticity markers in fresh and processed products, mainly due to their thermostability and high concentration white fish muscle. MALDI-TOF peptide profiles presented several major common peaks, but also some species-specific differential peaks, showing amino acid substitutions in the parvalbumin squences. The sequence of these peptides was obtained by MS/MS in an ion trap mass spectrometer followed by de novo sequence interpretation.

Unambiguous and highly-specific Merlucciidae species identification was then demonstrated by LC-MS/MS analysis of a tryptic digest from sarcoplasmic protein extracts, using the selected ion reaction monitoring (SIR) configuration, focused on the previously characterized specie-specific peptides in continuous MS/MS operation. The methodology developed provides a rapid and effective identification of fish products and constitutes an interesting authentication tool for fresh and processed seafood, guaranteeing the quality of the products to the consumers.