Abstract: The invention discloses a fusion protein and its preparation method for intermediate polypeptide of Semaglutide. The invention belongs to the technical field of genetic engineering and polypeptide preparation. The fusion protein comprises a fusion peptide, a protease cleavage site and a target main molecular sequence. By optimizing the fusion peptide sequence, changing the isoelectric point and hydrophilicity of the protein, the highest expression of the fusion protein is effectively increased to 13.1 g/L. Meanwhile, the properties of fusion protein are also improved, which is conducive to the development of subsequent extraction, enzyme digestion and purification processes. The yield of intermediate polypeptide after enzyme digestion is 3.62 g/L. The production cost of Semaglutide intermediate polypeptide Arg34GLP-1(9-37) is reduced from the source, which is conducive to industrial scale-up and suitable for industrial production.

Abstract: The invention relates to a low molecular weight sulfate chondroitin and a preparation method thereof. A low molecular weight chondroitin sulfate with the average molecular weight of less than 1000 Dalton can be obtained by a production process of chondroitin sulfate lyase degradation, deproteinization, filtration and sterilization and drying using macromolecular sulfate chondroitin as a raw material. The low molecular weight Chondroitin sulfate has a narrow molecular weight distribution range, the ratio of chondroitin sulfate disaccharide is 43˜60% and the ratio of chondroitin sulfate tetrasaccharide is 30˜45%, the sum of chondroitin sulfate disaccharide and chondroitin sulfate tetrasaccharide is more than 87%, the total oligosaccharide content of low molecular weight chondroitin sulfate is more than 97% and the protein content is less than 0.

Abstract: The invention belongs to the technical field of polypeptide preparation methods, and in particular relates to a high-purity ACTH (human sequence) or analogue and large-scale preparation method thereof. The main steps include: amino acids are coupled from the C-terminal to the N-terminal by Fmoc solid-phase synthesis method to obtain the crude ACTH (human sequence) or analogue peptidyl-resin with protective groups, wherein the reaction temperature of C-15 peptide synthesis is 40-60° C. After cleavge and precipitation, the crude product of ACTH (human sequence) or analogue is obtained, and then the high-purity product is obtained by liquid chromatography. The chromatographic purity of ACTH (human sequence) or analogue prepared by the invention is more than 99%, the stability is good, and the yield of the target peptide is ?63%.