PROBLEM TO BE SOLVED: To obtain a new peptide and to provide use thereof. SOLUTION: This invention provides a new peptide and a DNA encoding the peptide； medicines containing the peptide or the DNA； a screening method/a screening kit for a compound or its salt promoting or inhibiting the activity of the peptide； compounds or salts thereof obtained by the screening； medicines containing the compounds or salts thereof, and the like. The peptide and the DNA encoding the peptide are usable in, for example, diagnosing, treating and preventing digestive diseases, or the like. Moreover, the peptide is useful as a reagent for screening a compound or its salt promoting or inhibiting the activity of the peptide.
