Long-acting oxyntomodulin hybrid peptide, preparation method therefor, and application thereof

A compound having a general formula His-Xaa1-PP1-Xaa2-PP2-Xaa3 and its pharmaceutically acceptable salt, wherein

• PP1 is a polypeptide selecting from the group of polypeptides having the amino acid sequences shown as SEQ ID NO.:02, SEQ ID NO.:04 and SEQ ID NO.:05;
• PP2 is a polypeptide selecting from the group of polypeptides having the amino acid sequences shown as SEQ ID NO.:03, SEQ ID NO.:06, SEQ ID NO.:07 and SEQ ID NO.:08;
• PP1 is the polypeptide selecting from the group of polypeptides having the amino acid sequences shown as SEQ ID NO.:02, SEQ ID NO.:04 and SEQ ID NO.:05 when PP2 is the polypeptide having the amino acid sequence shown as SEQ ID NO.:03;
• PP1 is the polypeptide having the amino acid sequence shown as SEQ ID NO.:05 when PP2 is the polypeptide selecting from the group of polypeptides having the amino acid sequences shown as SEQ ID NO.:06, SEQ ID NO.:07 and SEQ ID NO.:08;
• wherein
• Xaa1 is selected from the group consisting of Gly, Aib, D-Ser, Ser, Arg, Asn, Asp, Cys, Gln, Glu, His, Ile, Leu, Lys, Met, Phe, Pro, Thr, Trp, Tyr and Val;
• Xaa2 is selected from the group consisting of Cys,
• wherein X is —CH3 or —COOH;
• Y is —NH—CO— or —CO—NH—;
• n is a natural number selected from 0 to 20;
• m is a natural number selected from 1 to 20;
• and
• Xaa3 is Ser-OH or Ser-NH2.