<unk>  is a member of the gastrin/cholecystokinin family of peptide hormones and is very similar in structure to gastrin, another gastrointestinal hormone.<unk>  and gastrin share the same five C-terminal amino acids.<unk>  is composed of varying numbers of amino acids depending on post-translational modification of the 150-amino acid precursor, preprocholecystokinin. Thus, the<unk>  peptide hormone exists in several forms, each identified by the number of amino acids it contains, e.g.,<unk> -58,<unk> -33,<unk> -22 and<unk> -8.<unk> 58 assumes a helix-turn-helix configuration. Biological activity resides in the C-terminus of the peptide. Most<unk>  peptides have a sulfate group attached to a tyrosine located seven residues from the C-terminus (see tyrosine sulfation). This modification is crucial for the ability of<unk>  to activate the<unk>  A receptor. Nonsulfated<unk>  peptides also occur, which consequently cannot activate the<unk> -A receptor, but their biological role remains unclear.
Cholecystokinin
Gastric inhibitory polypeptide
Glucagon-like peptide-1
Gluten exorphin
Incretin
Enterogastrone
Delta-sleep-inducing peptide
Hyperforin