P82 Peptide fraction identification by SE-HPLC and LC-MS/MS analysis of the body mucus from Portugal coastal fish Halobatrachus didactylus

M. Cunha*, E. R. Coscueta, M. E. Brassesco, F. Almada, D. Gonçalves, M. Manuela Pintado

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review



The mucus covers the fish's body, working as a protective barrier. Besides physical protection, mucus provides molecules that protect the fish from pathogens damaging 1,2. These include antimicrobial peptides secreted in the mucus, which play an essential role in defense against microbial pathogens since these belong to the innate immune system2,3. In this study, two adult Halobatrachus didactylus individuals were captured from the wild in Sesimbra. Then, mucus collection was performed by scraping the dorsal-lateral body of the fish with a sponge. Our objective was the identification of new peptides with bioactive potential in mucus samples by chromatography analysis. Size exclusion highperformance liquid chromatography (SE-HPLC) analysis performed on mucus samples from the two individuals revealed a similar profile with an intense highlight peak which resulted in a distribution of about 775 Dalton. With interest in that peak, the two mucus samples were pooled for fractionation by SEC. The resulting fraction was analyzed by liquid chromatography-tandem mass spectrometry (LCMS/MS) to identify the most probable peptide sequences. Identification from databases did not provide reliable results, indicating a lack of information on the matrix analyzed. We resorted to de novo sequencing with good results using PEAKS Studio software. Five identified peptides were selected according to their bioactivities predicted in silico. Furthermore, the five identified peptides were synthesized, and the molecular size was validated by SE-HPLC analysis. Overall, this chromatographic approach enabled the identification of promising peptides, which bioactivities will be evaluated in vitro in future work.
Original languageEnglish
Title of host publicationLivro de resumos do 12º Encontro Nacional de Cromatografia e XIV WARPA
EditorsSílvia M. Rocha
Place of PublicationLisboa
PublisherSociedade Portuguesa de Química
Number of pages1
ISBN (Electronic)9789898124371
Publication statusPublished - 6 Dec 2022
Event12º Encontro Nacional de Cromatografia - Universidade de Aveiro, Aveiro, Portugal
Duration: 6 Dec 20228 Dec 2022


Conference12º Encontro Nacional de Cromatografia
Abbreviated title12ENC
Internet address


  • Fish
  • Mucus
  • Halobatrachus didactylus
  • LC-MS/MS
  • Peptides


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