Abstract: Glucagon-like peptide-1(GLP-1) is an endogenous hormone which is mainly secreted by intestinal endocrine L-cells and has the effect of lowering blood glucose. To screen and identify active peptides promoting GLP-1 secretion from chromium-enriched yeast proteins, the chromium-enriched yeast proteins were digested with simulated gastric and intestinal fluid. Under the guidance of promoting GLP-1 secretion activity, the anti-digestive active peptides were isolated and purified by ultrafiltration and gel chromatography, and their amino acid sequences were identified by liquid chromatograph-mass spectrometer(LC-MS). On this basis, active peptides were artificially synthesized by solid phase method. GLP-1 content in NCI-H716 cells and mouse ileum was determined by ELISA, and intracellular $ Ca^{2+} $ content was determined by $ Ca^{2+} $ kit. The results showed that the protein hydrolysates of chromium-enriched yeast contained peptide sequences that promoted GLP-1 secretion. An octapeptide, P-II, was obtained by isolation, purification, and structural identification. The amino acid sequence of P-II was PSIVGRPR and its molecular weight was 881.04 Da. In situ administration of cells and mouse jejunum showed that P-II could significantly promote the secretion of GLP-1 from intestinal endocrine L-cells, which might be related to the increase of intracellular $ Ca^{2+} $ level. These studies indicate that chromium-enriched yeast proteins contain active peptides that promote GLP-1 secretion, which provides theoretical basis for the application and development of chromium-enriched yeast in the prevention and treatment of diabetes.
Keywords: chromium-enriched yeast; active peptide; glucagon-like peptide-1(GLP-1); hypoglycemic action; structural identification
合肥工业大学学报自科版