Intrinsic factor (IF), cobalamin binding intrinsic factor,[5] also known as gastric intrinsic factor (GIF), is a glycoprotein produced by the parietal cells (in humans) or chief cells (in rodents) of the stomach. It is necessary for the absorption of vitamin B12 later on in the distal ileum of the small intestine.[6] In humans, the gastric intrinsic factor protein is encoded by the CBLIF gene.[5] Haptocorrin (transcobalamin I) is another glycoprotein secreted by the salivary glands which binds to vitamin B12. Vitamin B12 is acid-sensitive and in binding to haptocorrin it can safely pass through the acidic stomach to the duodenum.[7]
In the less acidic environment of the small intestine, pancreatic enzymes digest the glycoprotein carrier and vitamin B12 can then bind to intrinsic factor.[7] This new complex is then absorbed by the epithelial cells (enterocytes) of the ileum.[7] Inside the cells, vitamin B12 dissociates once again and binds to another protein, transcobalamin II; the new complex can then exit the epithelial cells to be carried to the liver.[8]
^ abcGRCh38: Ensembl release 89: ENSG00000134812 – Ensembl, May 2017
^ abcGRCm38: Ensembl release 89: ENSMUSG00000024682 – Ensembl, May 2017
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Pocock G, Richards C (2006). Human Physiology: The Basis of Medicine (3rd ed.). Oxford University Press. p. 230. ISBN 978-019-856878-0.
^ abcFedosov SN (2012). "Physiological and Molecular Aspects of Cobalamin Transport". Water Soluble Vitamins. (review). Subcellular Biochemistry. Vol. 56. pp. 347–67. doi:10.1007/978-94-007-2199-9_18. ISBN 978-94-007-2198-2. PMID 22116708.
^Alpers DH, Russell-Jones G (May 2013). "Gastric intrinsic factor: the gastric and small intestinal stages of cobalamin absorption. A personal journey". (review). Biochimie. 95 (5): 989–94. doi:10.1016/j.biochi.2012.12.006. PMID 23274574.
Intrinsicfactor (IF), cobalamin binding intrinsicfactor, also known as gastric intrinsicfactor (GIF), is a glycoprotein produced by the parietal cells...
are the contact activation pathway (also known as the intrinsic pathway), and the tissue factor pathway (also known as the extrinsic pathway), which both...
vitamin B12 deficiency anemia that results from lack of intrinsicfactor. Lack of intrinsicfactor is most commonly due to an autoimmune attack on the cells...
epithelial cells in the stomach that secrete hydrochloric acid (HCl) and intrinsicfactor. These cells are located in the gastric glands found in the lining...
in order to ensure that impaired absorption of B12 (with or without intrinsicfactor) is not occurring due to damage to the intestinal mucosa from the B12...
gland contains the parietal cells that produce hydrochloric acid and intrinsicfactor, and chief cells that produce pepsinogen and gastric lipase. The pyloric...
developed countries is impaired absorption due to a loss of gastric intrinsicfactor (IF) which must be bound to a food-source of B12 in order for absorption...
secretion of essential substances such as hydrochloric acid, pepsin, and intrinsicfactor is impaired, leading to digestive problems. The most common are vitamin...
resulting from damage to the stomach, where intrinsicfactor is secreted, or damage to the ileum, where intrinsicfactor facilitates vitamin B12 absorption. These...
parietal cells in the stomach lining, preventing them from creating intrinsicfactor needed for the absorption of vitamin B12. It is the main and most common...
Cubilin is essential as a cell receptor recognizing the "vitamin B12-intrinsicfactor" complex, whereas amnionless is more involved in the receptor mediated...
requires successively three different protein molecules: haptocorrin, intrinsicfactor and transcobalamin II. Methylcobalamin Hydroxocobalamin Adenosylcobalamin...
stimulates the stomach's parietal cells to secrete acid and intrinsicfactor. Intrinsicfactor is needed to absorb vitamin B12 from food. The vagotomy reduces...
break down the glycoprotein and free the vitamin which then binds with intrinsicfactor. Food enters the mouth where the first stage in the digestive process...
anemia is caused by a lack of intrinsicfactor, which is required to absorb vitamin B12 from food. A lack of intrinsicfactor may arise from an autoimmune...
components). There are two distinct factors: Extrinsic factor, much more commonly known as vitamin B12 Intrinsicfactor, a glycoprotein produced by the parietal...
compatibility. Other factors are intrinsic in the individual, and it is these factors which are the basis of "true" memory span. Though numerous factors affect memory...
the factor that caused the fall, rather than all of the risk factors a patient has for falling. Risk factors may be grouped into intrinsicfactors, such...
present include parietal cells that secrete hydrochloric acid and intrinsicfactor, chief cells that secrete pepsinogen (this is a precursor to pepsin-...
is encoded by the CUBN gene. Cubilin (CUBN) acts as a receptor for intrinsicfactor-vitamin B12 complexes. The role of receptor is supported by the presence...
motivation are discussed in the academic literature. Intrinsic motivation comes from internal factors like enjoyment and curiosity. It contrasts with extrinsic...
terminal ileum, lack of intrinsicfactor secreted from gastric parietal cells, or low gastric pH inhibiting attachment of intrinsicfactor to ileal receptors...
this is disputed lately. Arthrogryposis could also be caused by intrinsicfactors. This includes molecular, muscle- and connective tissue development...
the cytoskeleton Interstitial fluid, the liquid outside of a cell Intrinsicfactor, produced by the stomach If-then-else, a conditional statement in computer...
announcements Pernicious anemia, anemia that results from lack of intrinsicfactor Primary aldosteronism, excess production of the hormone aldosterone...
Intrinsicfactor (IF) is a glycoprotein, with a molecular weight of 45 kDa. In the duodenum, the free vitamin B12 attaches to the intrinsicfactor (IF)...
determines factor prices. Classical and Marxist economists argue that factor prices decided the value of a product and therefore the value is intrinsic within...
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