title: Impurity profiling quality control testing of synthetic peptides using liquid chromatography-photodiode array-fluorescence and liquid chromatography-electrospray ionization-mass spectrometry: the obestatin case.
abstract: Following several conflicting publications, the inability to reproduce the original findings on in vitro obestatin binding and activation of GPR39 receptors was recently reported by its discoverers, and several hypotheses to rationalize these findings were proposed. Based on one of these postulations (i.e., presence of impurities), peptide identity and impurity profiles were thoroughly evaluated on obestatin peptides obtained from five different manufacturers, as used by the different research groups. We found that one of the products examined was in reality a totally different peptide and that the quality of two-thirds of the other peptides was insufficient for in vitro and in vivo experiments (i.e., peptide purity less than 95% and/or individual impurities exceeding 1%). These observations question the divergent conclusions reported in the literature about the activity of obestatin. Therefore, we strongly recommend appropriate quality control testing before using any peptides for biomedical research purposes.
authors.affiliation: Drug Quality and Registration group, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium. Bart.DeSpiegeleer@UGent.be
authors.forename: Bart
authors.initials: B
authors.lastname: De Spiegeleer
authors.forename: Valentijn
authors.initials: V
authors.lastname: Vergote
authors.forename: Adel
authors.initials: A
authors.lastname: Pezeshki
authors.forename: Kathelijne
authors.initials: K
authors.lastname: Peremans
authors.forename: Christian
authors.initials: C
authors.lastname: Burvenich
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D054439:Ghrelin; D006801:Humans; D036361:Peptide Hormones / Q000032:analysis / Q000138:chemical synthesis / Q000592:standards; D010455:Peptides / Q000032:analysis* / Q000138:chemical synthesis / Q000592:standards; D011786:Quality Control; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry
chemical_list: D054439:Ghrelin; D036361:Peptide Hormones; D010455:Peptides; C505799:obestatin, human