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Characterization of naturally occurring peptides in the skin secretion of Rana pipiens frog reveal pipinin-1 as the novel insulin-releasing agent

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Marenah, L, Flatt, Peter, Orr, DF, Shaw, C and Abdel-Wahab, Yasser (2005) Characterization of naturally occurring peptides in the skin secretion of Rana pipiens frog reveal pipinin-1 as the novel insulin-releasing agent. JOURNAL OF PEPTIDE RESEARCH, 66 (4). pp. 204-210. [Journal article]

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DOI: 10.1111/j.1399-3011.2005.00287.x

Abstract

Naturally occurring insulinotropic peptides were isolated from the skin secretions of Rana pipiens frogs. Crude secretions (50 mg; 5-10 frogs) obtained by mild electrical stimulation of the dorsal skin surface were purified by reversed-phase high-performance liquid chromatography ( HPLC) yielding 80 fractions. In acute incubations with glucose-responsive BRIN-BD11 cells, fractions 40-47 (band 1) and fractions 60-65 (band 2) showed significant 1.7-6.7-fold increases in insulin-releasing activity (P < 0.001) compared with 5.6 mM glucose alone. Pooled fractions in bands 1 and 2 were rechromatographed yielding a total of seven peaks capable of subsequent 1.2-1.8-fold stimulation of insulin release. Final purification by HPLC to single homogenous peaks revealed one prominent peptide (peak 4.1) with insulin- releasing activity which lacked effects on cell viability. Electrospray mass spectrometric analysis of this peptide indicated molecular mass of 2562.6 Da. Determination of the primary amino acid sequence of this peptide revealed a 24-amino acid sequence: FLPIIAGVAAKVFPKIFCAISKKC. Database search showed a 100% homology to histamine-releasing pipinin-1. In conclusion, this study revealed the skin secretions of Rana pipiens to be a rich source of insulin- releasing peptides. The discovery of insulinotropic activity for pipinin-1, initially characterized as an antimicrobial is interesting and merits further investigation.

Item Type:Journal article
Faculties and Schools:Faculty of Life and Health Sciences
Faculty of Life and Health Sciences > School of Biomedical Sciences
Research Institutes and Groups:Biomedical Sciences Research Institute
Biomedical Sciences Research Institute > Diabetes
ID Code:2994
Deposited By:Professor Peter Flatt
Deposited On:18 Dec 2009 09:53
Last Modified:11 Jun 2010 10:33

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