Transcobalamin (TC) is a 43-kDa nonglycosylated protein synthesized in most tissues and encoded by a gene located on chromosome 22. It binds to Cbl with a high affinity and delivers blood Cbl to cells by receptor-mediated endocytosis.

Transcobalamin is a protein that binds to Cbl (cobalamin) and transports it to cells through receptor-mediated endocytosis. It is synthesized in most tissues and its low concentration in serum indicates inadequate dietary intake or impaired assimilation. Transcobalamin is also influenced by genetic factors and is associated with homocysteine ...

Transcobalamin 2 deficiency. Transcobalamin 2 deficiency, caused by biallelic mutations in TCN2, interrupts the delivery of B12 to bone marrow cells, causing megaloblastic anemia, pancytopenia including low numbers/decreased function of T and B cells, and neutropenia with hyper-segmented granulocytes.

Transcobalamin (originally known as transcobalamin II) is a β-globulin protein produced by ileal enterocytes, endothelial cells, macrophages, and hepatocytes. Newly absorbed B12 bound to transcobalamin (holotranscobalamin or holoTC) travels through the portal circulation to the liver and to the rest of the bodily organs where it is taken up by ...

Transcobalamin is normally virtually unsaturated unless an individual is undergoing B 12 treatment. Transcobalamin should therefore be measured prior to vitamin B 12 treatment. Haptocorrin includes two glycosylated proteins, previously known as transcobalamins I and III, that differ in their sugar moiety.

The weak activity of transcobalamin promoter appears to be because of transcriptional suppression caused by the binding of transcription factor Sp3 to a proximally located GC/GT box (-179 to –165), and the basal activity of transcobalamin promoter is caused by the binding of transcription factor Sp1 to a positively acting GC box (-568 to -559 ...

Sep 1, 2020 · In blood circulation, vitamin B12 bound to transcobalamin II (TCN2) protein represents biologically active fraction, since it is the only vitamin B12 delivered to the cells by receptor mediated endocytosis (Quadros and Sequeira, 2013). So, any decrease or genetic variation in TCN2 protein may alter homocysteine, which is a risk factor for stroke.

Nov 1, 2020 · The cellular uptake of Cbl requires transcobalamin (TC), a plasma protein secreted by most cells but the vascular endothelium secretes copious amounts of this protein and is the likely source for most of the circulating TC [2]. TC has a relatively short plasma half-life of about 60–90 min binds Cbl with high affinity and carries about a third ...

Jan 1, 2009 · Cellular uptake of cobalamin (Cbl, vitamin B 12) in mammalian cells is mediated by receptors expressed on the cell surface. 1 Transcobalamin (TC, TCII), a plasma protein secreted by the endothelial cells, binds the Cbl absorbed in the distal ileum and carries between 10% and 30% of the total circulating Cbl. 2, 3 TC saturated with Cbl specifically binds to the receptor …

Jun 1, 2005 · Background: A common genetic polymorphism [transcobalamin (TC) 776C→G] may affect the function of transcobalamin, the protein required for vitamin B-12 cellular uptake and metabolism. Remethylation of homocysteine is dependent on the production of 5-methyltetrahydrofolate and adequate vitamin B-12 for the methionine synthase reaction.