To investigate the bioactive component from the skin secretion of
Amolops loloensis
, isolated peaks with insulin-releasing activity were purified and structurally determined. Skin secretions were isolated by Gel filtration and Reversed phase high-performance liquid chromatography, and tested with insulin-releasing assay. The amino acid sequence of bioactive peak was determined by Edman degradation and identified by gene clone method. A 16-amino peptide with obvious insulin-releasing activity was obtained and sequenced as FMPIVGKSMSGLSGKL-NH
2 , which was designated amolopin-1. The precursor peptide composed of 64 amino acid residues deduced from cloned skin cDNA (open reading frame 192 bp) exhibited a highly-conserved signal peptide (22aa), an acidic amino acid residue-rich domain and an amolopin-1 encoding domain. Structural alignment with database records revealed that a novel insulinotropic peptide was obtained from skin secretion of
Amolops loloensis therefore further study of its acting mechanism and pharmacokinetics may lead to the discovery of a new treatment for diabetes.
