Polypeptide compound taking PD-1 receptor as target point as well as preparation method and application thereof

The invention discloses a polypeptide compound taking a PD-1 receptor as a target spot. The polypeptide compound comprises a compound 1, a compound 2, a compound 3, a compound 4 and a compound 5, wherein the amino acid sequences of the compounds 1-5 are as shown in SEQ ID NO: 1-5. The invention also discloses a preparation method of the polypeptide compound taking the PD-1 receptor as the target spot, and the preparation method comprises the following processes: coupling amino acids of compounds 1-5 to solid-phase resin in sequence according to a peptide sequence by utilizing a solid-phase synthesis mode, cracking by a cutting reagent, freeze-drying, preparing and purifying to obtain the target compound. The invention also discloses application of the polypeptide compound taking the PD-1 receptor as the target spot in preparation of analgesic drugs. According to the small molecule polypeptide, compounds 1-5 can be combined with PD-1, and the obvious inhibition effect on inflammatory pain and visceral pain is