Proinsulin

insulin
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
SymbolINS
NCBI gene3630
HGNC6081
OMIM176730
RefSeqNM_000207
UniProtP01308
Other data
LocusChr. 11 p15.5
Search for
StructuresSwiss-model
DomainsInterPro

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]

  1. ^ "Entrez Gene: INS insulin".
  2. ^ 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.
  3. ^ a b c d "Interpretation for 80908 Proinsulin, Plasma". www.mayomedicallaboratories.com. Archived from the original on 2017-10-04. Retrieved 2017-03-09.
  4. ^ 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.
  5. ^ 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.