The method of preparing exenatide

The present invention belongs to the technical field of the preparation method of polypeptide drugs, particularly to a method of preparing exenatide. The present invention solves the technical problem existing difficulties prepared isolated and purified, low overall yield and product purity. The present invention solves the above technical problem aspect is to provide a method for preparing exenatide. The method comprising: using solid phase peptide resin SYSTEM exenatide, and then acid hydrolysis to give crude exenatide, exenatide finally give the pure product; wherein the solid phase method of polypeptide: amino resin by solid phase coupling joint the following protected amino acids are sequentially into law access sequence corresponding protected amino acids or fragments, preparing exenatide resin: RW (Trt) -X (OtBu) -Thr (tBu) -Phe-Thr (tBu) -Ser (tBu) -Asp (OtBu) -Leu-Ser (tBu) -Lys (Boc) -Gln (Trt) -Met-Glu (OtBu) -Glu (OtBu) -Glu (OtBu) -Ala-Val-Arg (Pbf) -Leu -Phe-Ile-Glu (OtBu) -Trp (Boc) -Leu-Lys (Boc) -Y (Trt) - Ser (tBu) -Z (tBu) -Ala-Pro-Pro-Pro-Ser (tBu) - amino resin; wherein, R is Fmoc, Boc or H, W is His-Gly, X is Glu-Gly, Y is Asn-Gly-Gly-Pro, Z is Ser-Gly. The present invention provides a new method to shorten the production cycle, improve the product purity and yield.