caa a22 4500 378919989 CHVBK 20180305123602.0 cr unu---uuuuu 161128e20040413xx s 000 0 eng 10.1515/BC.2004.027 doi (NATIONALLICENCE)gruyter-10.1515/BC.2004.027 Skin secretion of the toad Bombina variegata contains multiple insulin-releasing peptides including bombesin and entirely novel insulinotropic structures [Elektronische Daten] [L. Marenah, P. R. Flatt, D. F. Orr, S. McClean, C. Shaw, Y. H. A. Abdel-Wahab] Skin secretions of the toad Bombina variegata were evaluated for the isolation and characterisation of insulinotropic peptides. Crude secretions obtained from young adult toads by mild electrical stimulation of the dorsal skin surface were purified by reverse phase HPLC yielding 44 peaks. In acute incubations with glucose-responsive BRIN-BD11 cells, peaks 21, 22, 23, 24 and 25 showed a 1.5-3.5-fold increase in insulin release compared with 5.6 mM glucose alone (p<0.001; n=3). Structural analyses of the purified insulinreleasing peaks were performed by automated Edman degradation and mass spectrometry. Peptides represented by peaks 21, 22 and 23 had molecular masses of 1641.7 Da, 1662.6 Da and 1619.8 Da respectively. These peptides were unblocked by removal of pyroglutamic acid from the Nterminus prior to Edman degradation, revealing lengths of 14 amino acids. Peak 21 yielded a primary structure of PyrQRLGHQWAVGHLM, which a data base search revealed as an analogue of bombesin (His6 bombesin), while peak 23 was an exact match of bombesin (PyrQRLGNQWAVGHLM) originally isolated from Bombina bombina. Peak 22 indicated a primary structure of PyrDSFGNQWARGHFM (72% homology with bombesin). Peaks 24 and 25 revealed entirely novel insulinotropic peptides with molecular masses and primary structures of 1650.5 Da and 2300.0 Da and GKPFYPPPIYPEDM (GM-14) and IYNAICPCKHCNKCKPGLLAN (IN-21) respectively. Preliminary studies on the mechanisms underlying the insulinotropic actions of peaks 21, 22, 23 and 24 suggest possible involvement of a cAMPdependent, G protein-insensitive pathway. These data indicate that Bombina variegata skin secretions contain peptides with insulinreleasing activity, which may have mammalian counterparts and prove useful for possible exploitation as antidiabetic agents from natural resources. Copyright © 2004 by Walter de Gruyter GmbH & Co. KG Biochemistry nationallicence Molecular biology nationallicence Cellular biology nationallicence Marenah L. aut Flatt P. R. aut Orr D. F. aut McClean S. aut Shaw C. aut Abdel-Wahab Y. H. A. aut Biological Chemistry Walter de Gruyter 385/3-4(2004-04-13), 315-321 1431-6730 385:3-4<315 2004 385 bchm https://doi.org/10.1515/BC.2004.027 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1515/BC.2004.027 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Marenah L. aut NATIONALLICENCE 700 1- Flatt P. R. aut NATIONALLICENCE 700 1- Orr D. F. aut NATIONALLICENCE 700 1- McClean S. aut NATIONALLICENCE 700 1- Shaw C. aut NATIONALLICENCE 700 1- Abdel-Wahab Y. H. A. aut NATIONALLICENCE 773 0- Biological Chemistry Walter de Gruyter 385/3-4(2004-04-13), 315-321 1431-6730 385:3-4<315 2004 385 bchm CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter