Proglucagon is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
that is cleaved from preproglucagon. Preproglucagon in humans is encoded by the ''GCG''
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
Proglucagon is a precursor of
glucagon, and several other components. It is generated in the
alpha cells of the
pancreas
The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e. it has both an en ...
and in the intestinal
L cell
Enteroendocrine cells are specialized cells of the gastrointestinal tract and pancreas with endocrine function. They produce gastrointestinal hormones or peptides in response to various stimuli and release them into the bloodstream for systemic ef ...
s in the distal ileum and colon. It is also cleaved into the following components in different organs:
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Signal peptide (1-20) – removed from preproglucagon to form proglucagon
*
Glicentin (21–89)
*
Glicentin-related pancreatic polypeptide (GRPP, 21-50)
*
Oxyntomodulin Oxyntomodulin (often abbreviated OXM) is a naturally occurring 37-amino acid peptide hormone found in the colon, produced by the oxyntic (fundic) cells of the oxyntic (fundic) mucosa. It has been found to suppress appetite.
The mechanism of actio ...
(OXY or OXM, 53–89)
*
Glucagon (53–81)
* Glucagon-like peptide 1 (
GLP-1
Glucagon-like peptide-1 (GLP-1) is a 30- or 31-amino-acid-long peptide hormone deriving from the tissue-specific posttranslational processing of the proglucagon peptide. It is produced and secreted by intestinal enteroendocrine L-cells and certa ...
, 92–128) – first seven residues further cleaved
* Glucagon-like peptide 2 (
GLP-2 Glucagon-like peptide-2 (GLP-2) is a 33 amino acid peptide with the sequence HADGSFSDEMNTILDNLAARDFINWLIQTKITD (see Proteinogenic amino acid) in humans. GLP-2 is created by specific post-translational proteolytic cleavage of proglucagon in a process ...
, 146–178)
Proglucagon itself is a protein with three repeats of slightly different
secretin family
Glucagon/gastric inhibitory polypeptide/secretin/vasoactive intestinal peptide hormones are a family of evolutionarily related peptide hormones that regulate activity of G-protein-coupled receptors from the secretin receptor family.
A number of ...
hormones to be cleaved to form mature hormones.
References
Further reading
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External links
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{{Proglucagon
Pancreatic hormones
Precursor proteins