Proteomic analysis of white muscle tissue of Engraulis encrasicolus (European anchovy) – Initial results

Background/Aim: Engraulis encrasicolus is a small pelagic species, commonly known as European anchovy, which in Greece is mainly fished in the North Aegean Sea and the Thermaikos Gulf. Anchovy fisheries make up 1/10 of the total annual catch of the greek fishing fleet, therefore fishing and trading of this species plays an important role in the local and national economy. Moreover, anchovy is of high nutritional value for human consumption and an integral part of the mediterranean diet. In this prospect, studies investigating the preservation of its nutritional value, either as a fresh or processed product, are of both scientific and commercial interest. Within this context, we embarked on the characterization of the proteome of the white muscle of anchovy, as this corresponds to the major portion of the edible part of the fish.
Materials and Methods: White muscle tissue samples excised from n=3 fish were investigated. Total proteins were extracted from tissues processed by the FASP method and analyzed using nano-liquid chromatography coupled to an Orbitrap mass spectrometer (nanoLC-ESI-Orbitrap MS/MS). MS data underwent bioinformatics processing using known sequences from other fish species available on the SWISSPROT/UniProt database, since there exist no data on the European anchovy proteins. Results: Our analyses resulted in identification of 386 proteins, of which one belonged to the parasitic worm Anisakis pegreffi. Protein stratification according to biological process, showed that 30.5% of proteins were of unknown function, 11.1% were proteins involved in metabolic processes, 9.9% were signaling proteins, 9.3% were transporters, 9.1% were involved in protein modification, 3.9% were cytoskeletal proteins and the rest 24.3% had other functions. Conclusion: The present study represents the first attempt to characterize the proteome of European anchovy. Our results contribute to the enrichment of the corresponding databases. Moreover, they form the basis for the identification of protein-markers of the species’ spoilage process.