CCK (26-31) (non-sulfated) is the N-terminal fragment of CCK, a peptide hormone found in the gut and brain that stimulates digestion, regulates satiety, and is associated with anxiety. CCK (26-31) is also less active in non-sulfated than in sulfated form[1].
1. Raybould, H.E., and Lloyd, K.C. Integration of postprandial function in the proximal gastrointestinal tract. Role of CCK and sensory pathways Ann. N. Y. Acad. Sci. 713(1),143-156(1994).
2. Ondetti, M.A., Pluec, J., Sabo, E.F., et al. Synthesis of cholecystokinin-pancreozymin. I. The C-terminal dodecapeptide J. Am. Chem. Soc. 92(1),195-199(1970).