Isolation And Characterization Of A New Peptide Of Skin Secretion From Hyla raniceps (AMPHIBIA). 

^1,2Melo, J.A.T.; ^1,2,3Leite, J.R.S.A.; and ¹Bloch Jr, C.

1 Embrapa Recursos Genéticos e Biotecnologia, Brasília; 2 Laboratório Sabin, Brasília; 3 Universidade de Brasília, Depto de Biologia Celular, Brasília.

Amphibian skin secretions contain many biologically active compounds, such as biogenic amines, complex alkaloids and peptides. Within the latter class of molecules, a large number of peptide antibiotics have been isolated and characterized from different amphibian species. Antimicrobial peptides are considered to be the effector molecules of the innate immunity, acting as a first line of defense against bacterial infections. A number of different types of bioactive peptides have been identified from the glandular skin secretions of Brazilian anurans from the Hyla genus. This work describes the isolation, molecular mass characterization and sequencing of a new peptide from Hylaraniceps. The extract obtained by mild electric stimulation of the frogs’ skin glands was purified by RP-HPLC (Shimadzu Corporation, Kyoto, JP) using both semi-preparative and analytical columns. The peptide named Hr4 has been eluted at 38.5 percent of acetonitrile. Further, monoisotopic mass analysis and molecular sequencing were performed by using an ESI-QTOF Ultima API Mass Spectrometer (Waters/Micromass, Manchester, UK) under high resolution W-mode. Monoisotopic peptide mass was Hr4 = 3038.83 Da. N-terminal sequencing has revealed that the peptide constitute a novel molecule, as shown by the lack of similarity to others from databanks. Total peptide sequencing and biological assays will be performed in order to assess their physiological relevance to the frog and possible applications to animal health.

Support : EMBRAPA-CENARGEN, CNPq, UnB and LABORATORIO SABIN.

Correspondence to: taquita@cenargen.embrapa.br