title: A Novel Insulinotropic Peptide from the Skin Secretions of Amolops loloensis Frog.
abstract: Various kinds of biologically active peptides have previously been isolated from the skin secretions of Amolops loloensis frog, such as antimicrobial peptides, bradykinin-like peptides and algesic peptides. A novel insulinotropic peptide named amolopin was identified in A. loloensis frog's skin secretion. Its primary structure sequence was determined by Edman degradation as: FLPIVGKSLSGLSGKL-NH2. BLAST search indicates that the amino acid sequence of amolopin is quite different from other known insulin secretagogues, including mastoparan, exendins and α-latrotoxin, nor does it like incretins (e.g. glucagons like peptide-1 and glucose-dependent insulinotropic ploypeptide) either. However, amolopin shows certain structural similarity with amphibian antimicrobial temporins and vespid chemotactic peptides isolated from Vespa magnifica. Amolopin can stimulate insulin release in INS-1 cells in a dose-dependent manner. Primary investigation on its action mechanisms reveals that amolopin does not increase the influx of Ca(2+). In conclusion, a novel 16-amino acid peptide with insulin-releasing activity is initially discovered from the skin secretion of A. loloensis frog. Further work is necessary to evaluate its potential as novel anti-diabetic candidate.
authors.affiliation: School of Biological Sciences, Nanjing Agriculture University, Nanjing, 210095, Jiangshu, China.
authors.forename: Guo-Xiang
authors.initials: GX
authors.lastname: Mo
authors.forename: Xue-Wei
authors.initials: XW
authors.lastname: Bai
authors.forename: Zong-Jie
authors.initials: ZJ
authors.lastname: Li
authors.forename: Xiu-Wen
authors.initials: XW
authors.lastname: Yan
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: He
authors.forename: Ming-Qiang
authors.initials: MQ
authors.lastname: Rong