This peptide hormone induces gall bladder contraction and the release of pancreatic enzymes in the gut. Its function in the brain is not clear. Binding to CCK-A receptors stimulates amylase release from the pancreas, binding to CCK-B receptors stimulates gastric acid secretion. cholecystokinin 58 and cholecystokinin 8, but not cholecystokinin 58 desnonopeptide, stimulate amylase release from the pancreas. cholecystokinin 58, but not cholecystokinin 8, increases bile-pancreatic volume. Binds to CCK-A receptors in the pancreas and CCK-B receptors in the brain. cholecystokinin 8 binds CCK-A receptors more potently than cholecystokinin 58, cholecystokinin 8 and cholecystokinin 58 bind CCK-B receptors with equal affinity. The precursor is cleaved by proteases to produce a number of active cholecystokinins. Cholecystokinin 58 occurs in both sulfated (CCK58(s)) and nonsulfated (CCK58(ns)) forms, which differ in their receptor-binding activities. CCK58(s) binds to the CCK-A receptor with high affinity, CCK58(ns) binds poorly to the CCK-A receptor. CCK58(s) and CCK58(ns) both bind the CCK-B receptor. The precursor is cleaved by ACE, which removes the Gly-Arg-Arg peptide at the C-terminus, leading to mature hormone. Belongs to the gastrin/cholecystokinin family.