Synthesis And Activity Of Glucagon-like Peptide-1 Analogs

Glucagon-like peptide-1(GLP-1)many physiological functions such as lowering blood sugar,reducing body weight,cardiovascular benefits,and improving ?-cells,and is the most promising drug in the treatment of diabetes and obesity.However,natural GLP-1 is rapidly degraded by DPP-IV,filtered by the kidney,and degraded by enzymes in the blood,with a half-life of less than 2 min in vivo.Therefore,in order to provide patients with more choices,the development of long-acting or oral glucagon-like peptide-1(GLP-1)analogues HSA become a hot research direction.The fusion protein of glucagon-like peptide-1 and human serum albumin(HSA)was innovatively synthesized in this study.Its structure is designed by mutating the eighth alanine of native GLP-1 to glycine or aminoisobutyric acid,and to increase Cys at the C-terminus or the 26 th lysine side chain as an intermediary for coupling human serum albumin.The compound was prepared by Fmoc solid phase synthesis,and the DTNP modified polypeptide chain formed a new disulfide bond.The product was purified by HPLC and the mass spectrum was consistent with the theoretical value.After directed coupling with albumin,SDS-PAGE analysis indicated a higher coupling rate.Animal experiments showed that the compound 2-HSA(GLP-1(7-37)(Ala8Gly)-Ala-Ala-Cys-HSA)had a hypoglycemic effect of 72 h,and the compound 5-HSA(GLP-1(7-37)(Ala8Aib)-Cys-HSA)had a hypoglycemic effect for up to 1 week.They had excellent hypoglycemic effect in both normal mice and type 2 diabetic rats,and insulin secretion is significantly increased.It is expected to be injected once a week for the treatment type 2 diabetes.In order to improve patient compliance,a preliminary study of oral GLP-1 analogues was performed.In this study,three GLP-1 analogues were designed by mutating the amino acids of liraglutide at position 8 and positions 30,33,34 and 35 by bioinformatics analysis.The analogs were prepared by Fmoc solid phase synthesis,purified by HPLC,and the results of mass spectrometry were consistent with the theoretical values.Subsequently,10 mM compound XLCA and 100 mM SNAC were separately added as auxiliary osmotic agents,and hydrolysis experiments were carried out in pepsin,trypsin and chymotrypsin respectively.The results of mass spectrometry showed that the addition of 100 mM SNAC resisted the action of trypsin hydrolyzing analog 1 in only 30 min,The addition of 10 mM compound XLCA to chymotrypsin and trypsin hydrolysis was significantly better than SNAC in most cases.Analog 1(GLP-1(7-37)(8Aib: 26K?: ?Glu-C16))was mostly hydrolyzed in chymotrypsin and trypsin at 37 ? for 24 h with the addition of 4 mM compound XLCA.Enteric preparations are prepared for oral administration.