Gastrin and cholecystokinin (CCK) [1,2] are structurally and functionally
related peptide hormones that function as hormonal regulators of various
digestive processes and feeding behaviors . They are known to induce gastric
secretion, stimulate pancreatic secretion, increase blood circulation and
water secretion in the stomach and intestine, and stimulate smooth muscle
contraction. Originally found in the gut, these hormones have since been
shown to be present in various parts of the nervous system. Like many other
active peptides they are synthesized as larger protein precursors that are
enzymatically converted to their mature forms. They are found in several
molecular forms due to tissue-specific post-translational processing. A
number of other peptides are known to belong to the same family:
Caerulein , an amphibian skin peptide, with a biological activity
similar to that of CCK or gastrin. There are different types of caerulein
precursors  in which a single or up to four copies of the peptide are
Leukosulfakinin I and II (LSK) [5,6] are peptides, isolated from cockroach,
that change the frequency and amplitude of contractions of the hindgut.
Drosulfakinins I and II  are putative CCK-homologs from Drosophila.
Those two peptides are part of a precursor sequence that was isolated
using a probe based on the sequence of CCK and LSK.
A chicken antrum peptide  which is a potent stimulus of avian gastric
acid but not of pancreatic secretion.
Cionin , a neuropeptide from the protochordate Ciona intestinalis.
The biological activity of gastrin and CCK is associated with the last five C-terminal residues. One or two positions downstream, there is a conserved
sulfated tyrosine residue. The signature pattern developed for this family of
peptides includes the biologically active C-terminal sequence as well as the
The residues in positions 4 and 6 of the pattern are respectively Trp
and Asp in vertebrate peptides, and His and Arg in insect peptides.
PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and
distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives
(CC BY-NC-ND 4.0) License, see prosite_license.html.