Cholecystokinin 83 (CCK83)

Cholecystokinin (CCK) is expressed in the central and peripheral nervous systems and functions as a neurotransmitter and neuroendocrine hormone. An 83-amino acid cholecystokinin peptide with a sulfated tyrosine and an amidated carboxyl terminus (CCK-83) was purified from human intestinal mucosa. The purified peptide was chemically characterized, and its bioactivity was compared to CCK-8. Several post-translational processing steps such as cleavage at basic residues, sulfation, and amidation are necessary to form biologically active cholecystokinin from its nascent prepropeptide. The discovery of CCK-83 gives new insight into the order of preprohormone processing.The characterization of biologically active CCK-83 with a sulfated tyrosine and an amidated carboxyl terminus establishes the site of signal peptidase action and suggests an order of post-translational modifications that give rise to the various molecular forms of cholecystokinin.