Abstract: Objective: To screen phage particles capable of mimicking citrinin. Methods: An anti-citrinin monoclonal antibody was used as ligand. Biopanning was done to screen the mimotope from a phage random 7 peptide library and a phage random 12 peptide library. These libraries were displayed as a fusion protein with the coat protein Ⅲ of filamentous phage M13. The positive clones were identified by ELISA, and the inserted amino sequences were deduced by DNA sequencing.Results After three rounds of panning, 20 positive clones could bind to the antibody,and the binding could be blocked by free citrinin in the phage random 7 peptide library; After three rounds of panning, 33 positive clones could bind to the antibody,and the binding could be blocked by free citrinin in the phage random 12 peptide library. The common amino sequence of the mimicking epitope was XHKXXXX. A competitive ELISA immunoassay was established with clone P10 of the phage random 7 peptide library, the 1inear range of the inhibition curves was between 10ng/ml and 325ng/ml; the detecting limitation was 10ng/ml. A competitive ELISA immunoassay was established with clone P1 of the phage random 12 peptide library,the 1inear range of the inhibition curves was between 10ng/ml and 439ng/ml; the detecting limitation was 10ng/ml. Conclusion: The phage display technique could be successfully applied to screen the mimotope of citrinin. The conserved His and Lys indicate that it maybe play a key role in citrinin receptorb indingt o citrinin.

Key words: phage display peptide 1ibrary, mimotope, citrinin, monoclonal antibody, immunoassay