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
Glucagon is a peptide hormone, produced by alpha cells of the pancreas. It raises concentration of glucose and fatty acids in the bloodstream, and is considered to be the main catabolic hormone of the body. It is also used as a medication to tre ...
, and several other components. It is generated in the
alpha cell
Alpha cells (α cells) are endocrine cells that are found in the Islets of Langerhans in the pancreas. Alpha cells secrete the peptide hormone glucagon in order to increase glucose levels in the blood stream.
Discovery
Islets of Langerhans were ...
s 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 ...
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:
*
Signal peptide
A signal peptide (sometimes referred to as signal sequence, targeting signal, localization signal, localization sequence, transit peptide, leader sequence or leader peptide) is a short peptide (usually 16-30 amino acids long) present at the N-te ...
(1-20) – removed from preproglucagon to form proglucagon
*
Glicentin (21–89)
*
Glicentin-related pancreatic polypeptide (GRPP, 21-50)
*
Oxyntomodulin (OXY or OXM, 53–89)
*
Glucagon
Glucagon is a peptide hormone, produced by alpha cells of the pancreas. It raises concentration of glucose and fatty acids in the bloodstream, and is considered to be the main catabolic hormone of the body. It is also used as a medication to tre ...
(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, 146–178)
Proglucagon itself is a protein with three repeats of slightly different
secretin family 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