This family contains a number of defence peptides secreted from the skin of amphibians, including the opiate-like dermorphins and deltorphins, and the antimicrobial dermoseptins and temporins. The alignment for this family consists of the signal peptide and propeptide regions and does not include the active peptides [1] [2].Family members such as the peptide leucine arginine (pLR) belongs to a class of cyclic peptides isolated from frog skin. Its primary sequence is similar to the reactive loop of plant Bowman-Birk inhibitors (BBI), and the circular sunflower trypsin inhibitor-1 (SFTI-1) and to HV-BBI, an isolated peptide from amphibian skin with trypsin-inhibitory activity. pLR is a highly potent trypsin inhibitor, with therapeutic potential. A study describing immunomodulatory properties of pLR showed that the peptide is a potent activator of histamine release [3]. Other members such as Phylloseptins are antimicrobial peptides of 19-20 residues and carry an amidated C-terminus [4].

1: Solution structure of the antimicrobial peptide ranalexin and a study of its interaction with perdeuterated dodecylphosphocholine micelles. Vignal E, Chavanieu A, Roch P, Chiche L, Grassy G, Calas B, Aumelas A; Eur J Biochem 1998;253:221-228. PMID:9578480

2: Isolation and structure of novel defensive peptides from frog skin. Mor A, Nicolas P; Eur J Biochem 1994;219:145-154. PMID:8306981

3: Therapeutic potential of the peptide leucine arginine as a new nonplant bowman-birk-like serine protease inhibitor. Rothemund S, Sonnichsen FD, Polte T; J Med Chem. 2013;56:6732-6744. PMID:23988198

4: Solution NMR structures of the antimicrobial peptides phylloseptin-1, -2, and -3 and biological activity: the role of charges and hydrogen bonding interactions in stabilizing helix conformations. Resende JM, Moraes CM, Prates MV, Cesar A, Almeida FC, Mundim NC, Valente AP, Bemquerer MP, Pilo-Veloso D, Bechinger B; Peptides. 2008;29:1633-1644. PMID:18656510