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Journal №3 for 2011 г.
Article in number:
Synthesis of rat obestatin
Keywords: obestatin peptide synthesis obesity
Authors:
S.R. Seytablaeva, M.I. Titov
Abstract:
Obesity is a major public health problem associated with morbidity and mortality and continues to increase worldwide. The gastrointestinal tract and the pancreas release hormones regulating appetite and body weight. Ghrelin is a gut 28 amino-acids octanoylated peptide, which stimulates appetite. It is derived by posttranslational cleavage from preproghrelin of 117residues. Obestatin is a recently described 23 amino-acids peptide derived from preproghrelin too. It was identified by bioinformatic prediction. It has been reported to exhibit effects opposite to those of ghrelin and partially to reverse ghrelin effects. Obestatin decreases food intake and body weight gain, decelerates gastric emptying, promotes sleep in rat, inhibits water drinking. It has been described that obestatin effects on feeding behavior and an U-shaped dose-response relationship was found [4]: low doses (0.01-3 nmol/kg) and high doses (1-3 μmol/kg) were ineffective. Obestatin sequence was divided into fragments [H-AA1-8-OH, H-AA9-13-OH, H-AA14-23-NH2]. Synthesis was developed on the basis of solution and solid phase synthesis of protected peptide fragments followed by their assembly into the final product in solution. Stepwise synthesis of fragments was carried out using the orthogonal Fmoc/tBu strategy utilizing a 2-chlorotrityl-chloride resin as solid support with DIC/ HOBt in DMF as coupling agents. Couplings were performed with Fmoc-amino acids, DIC and HOBt in 2, 2.2 and 2.5 molar excess, respectively, for 90-120 min at room temperature. Completeness of the reaction was monitored by the Kaiser test. Rat Obestatin was obtained in 24% yield and 96+ purity after preparative HPLC.
Pages: 33-39
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