[Thr28, Nle31]-Cholecystokinin (25-33) is a bioactive peptide analog of Cholecystokinin (CCK), functioning as both a hormone and neurotransmitter within the gastrointestinal system and central nervous system, with a role in satiation by inhibiting food intake. Compared to native CCK8, this analog displays enhanced stability in acidic environments and resistance to air oxidation, attributed to the substitution of Methionine with Threonine at position 28 and Norleucine at position 31. Structurally, its predominant feature is a gamma-turn at Thr4, followed by a Gly5-separated helical region encompassing the C-terminal residues.