Insulin undergoes extensive posttranslational modification along the production pathway. Production and secretion are largely independent; prepared insulin is stored awaiting secretion. Both C-peptide and mature insulin are biologically active. Cell components and proteins in this image are not to scale.
Identifiers
Symbol
INS
NCBI gene
3630
HGNC
6081
OMIM
176730
RefSeq
NM_000207
UniProt
P01308
Other data
Locus
Chr. 11 p15.5
Search for
Structures
Swiss-model
Domains
InterPro
Proinsulin is the prohormone precursor to insulin made in the beta cells of the Pancreatic Islets, specialized regions of the pancreas. In humans, proinsulin is encoded by the INS gene.[1][2] The pancreatic islets only secrete between 1% and 3% of proinsulin intact.[3] However, because proinsulin has a longer half life than insulin, it can account for anywhere from 5–30% of the insulin-like structures circulating in the blood.[3] There are higher concentrations of proinsulin after meals and lower levels when a person is fasting.[3] Additionally, while proinsulin and insulin have structural differences, proinsulin does demonstrate some affinity for the insulin receptor. Due to the relative similarities in structure, proinsulin can produce between 5% and 10% of the metabolic activity similarly induced by insulin.[3]
Proinsulin is the final single chain protein structure secreted by cells before cleavage into mature insulin.[4] Proinsulin was discovered by Professor Donald F. Steiner of the University of Chicago in 1967.[5]
^"Entrez Gene: INS insulin".
^Bell GI, Pictet RL, Rutter WJ, Cordell B, Tischer E, Goodman HM (March 1980). "Sequence of the human insulin gene". Nature. 284 (5751): 26–32. Bibcode:1980Natur.284...26B. doi:10.1038/284026a0. PMID 6243748. S2CID 4363706.
^ abcd"Interpretation for 80908 Proinsulin, Plasma". www.mayomedicallaboratories.com. Archived from the original on 2017-10-04. Retrieved 2017-03-09.
^Assali NS, Clark KE, Zugaib M, Brinkman CR, Nuwayhid B (1995). "Effects of estrogenic hormones on uteroplacental hemodynamics and progesterone production in the sheep". International Journal of Fertility. 23 (3): 219–23. PMC 8333766. PMID 40897.
^Philipson LH, Bell G, Polonsky KS (January 2015). "Donald F. Steiner MD, 1930-2014: discoverer of proinsulin". Proceedings of the National Academy of Sciences of the United States of America. 112 (4): 940–1. Bibcode:2015PNAS..112..940P. doi:10.1073/pnas.1423774112. PMC 4313841. PMID 25561547.
humans, proinsulin is encoded by the INS gene. The pancreatic islets only secrete between 1% and 3% of proinsulin intact. However, because proinsulin has...
its signal peptide is removed by signal peptidase to form "proinsulin". As the proinsulin folds, opposite ends of the protein, called the "A-chain" and...
more peptide hormones. Examples of natural, human prohormones include proinsulin and pro-opiomelanocortin, but the most widespread prohormones in use are...
usually made biochemically with low blood glucose, elevated insulin, proinsulin, and C-peptide levels, and confirmed by localizing the tumour with medical...
As glucose stimulates insulin secretion, it simultaneously increases proinsulin biosynthesis through translational control and enhanced gene transcription...
a scenario for the action of proinsulin, insulin and insulin-like growth factors Upstream AUGs in embryonic proinsulin mRNA control its low translation...
through blood work revealing high insulin levels with low C-peptide and proinsulin. The production of glucose is blocked by alcohol. In those who misuse...
the precursor for a protein is often prefixed by pro-. Examples include proinsulin and proopiomelanocortin, which are both prohormones. Protein precursors...
insulinoma: hypoglycemia occurs with concurrent elevations of insulin, proinsulin and C peptide glucagonoma: the symptoms are not all due to glucagon elevations...
synthesized as preproinsulin, which yields proinsulin after the signal peptide has been cleaved. The proinsulin is then cleaved at two positions to yield...
products. For instance it was shown that the half-life of the recombinant proinsulin is increased 10-fold when the protein is secreted to the periplasmic space...
equal amounts to insulin. While being stored in pancreatic beta cells, proinsulin includes both insulin and C-peptide, which is freed before insulin secretion...
created as a precursor form called preproinsulin. This is converted to proinsulin and cleaved by C-peptide to insulin which is then stored in granules in...
occur in the secretory vesicles (for example insulin is cleaved from proinsulin in the secretory vesicles). Eventually, there is vesicle fusion with the...
differentially cleave proopiomelanocortin and they act together to process proinsulin and proglucagon in pancreatic islets. PC1/3 is an enzyme that performs...
proteins as collagen (zymogen: procolagen), hormones like insulin (zymogen: proinsulin) and proteins involved in development processes and apoptosis (programmed...
insulin effectively, resulting in increased insulin production; since proinsulin and proIAPP are cosecreted, this results in an increase in the production...
factor 1 (IGF-1, formerly known as somatomedin C), a hormone homologous to proinsulin. The liver is a major target organ of GH for this process and is the principal...
insulin antibody, i.e. insulin, proinsulin, and proinsulin-like material). The term is composed of hyper - high, proinsulin - immature insulin molecule,...
were observed in proteins such as fibrinopeptides and the C chain of the proinsulin molecule, which both have little to no functionality compared to their...
Tizard R, Naber SP, et al. (August 1978). "A bacterial clone synthesizing proinsulin". Proceedings of the National Academy of Sciences of the United States...
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