Analysis Of Bioactive Peptides And Structures, Functions Of A Novel Analgesic Peptide From Skin Of Ceratophrys Cranwelli

Amphibian is a biological treasure with great potentials. To be important natural resources, the ecological, academic, economic and cultural values of this kind of organism become more and more important. Varieties of bio-active substances in amphibian skins which play an important role in defense against invading factors have attracted the researchers all over the world. Ceratophrys cranwelli lives in Argentina, Bolivia and Brazil Grand Canyon. The albino of Ceratophrys cranwelli is called gold horned frog..In this study, the bio-active peptides in skin of Ceratophrys cranwelli have been researched by biochemical and molecular biological methods, and the new analgesic peptides have been identied.Skin cDNA library of Ceratophrys cranwelli was constructed.1X106independent clones were got in the skin cDNA library. Primer M13has been used to screen the clones in which length of inserting fragments is500-1000bp.142clones have been selected and sequenced.62among142clones could find homology sequences in NCBI. Such as cystatin, lysozyme, sodefrin. The bioactive peptides gene of Ceratophrys cranwelli is diversity.By screening the the skin cDNA library, a clone encoding amino acids multicopy sequence, has been found. Via translating, we know there are6copies in coding region. Each copy, composed of19amino acid residues, is not same. From N-terminal, the first two amino acids residues of each copy are K-R, it is classic site of post-translational processing in amphibian. Three peptides have been synthesized: CCAP1(TNGKGYQVENEDDYGDY),CCAP2(TNGKDYQVENEDDYGDY) and CCAP3(TSGNGYQEENENDYGDY). The antibacterial activity, anti-oxidize activity, bradykinin activity and analgesic activity of the three peptides have been detected. The peptides have analgesic activity. CCAP2has strong analgesic activity, the threshold rate of pain is increased to40%or more, and stable analgesia is maintained at a high level in60min. The analgesic peptide possesses potential clinic application value. It is a first report of analgesic peptides in Ceratophrys cranwelli.