Abstract: We used Chinese Hamster Ovary Cells over-expressing insulin receptors (CHO-IR) as screening targets to select peptide ligands of insulin receptors from a phage display random hexapeptide library. After one round of acid elution and three rounds of competitive elution, recombinant phage clones were enriched , the specific binding affinities of which were assayed with the method of cell-ELISA and the Ｋ_d values of the six most positive clones among them were calculated. Furthermore, we found several motifs from the sequences of thes esix clones. The result is very valuable for studying on the interaction betwee n insulin and insulin receptor and designing small molecular drugs.

Key words: insulin receptor, phage display random hexapeptide library, K_d value