- Arginine 336 and asparagine 333 of the human cholecystokinin-A receptor binding site interact with the penultimate aspartic acid and the C-terminal amide of cholecystokinin. Gigoux, V., Escrieut, C., Fehrentz, J.A., Poirot, S., Maigret, B., Moroder, L., Gully, D., Martinez, J., Vaysse, N., Fourmy, D. J. Biol. Chem. (1999)