TCN1 binds RCbl

Stable Identifier
Reaction [transition]
Homo sapiens
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Cobalamins in a +3 oxidation state and with various R groups (collectively, RCbl) are present in the diet as free molecules or complexed with dietary protein. The glycoprotein transcobalamin 1 (TCN1 aka haptocorrin, HC, TCII), produced by salivary glands (Morkbak et al. 2007, Wang et al. 2019), binds free RCbl and in the stomach binds RCbl freed by the initial digestion of dietary protein. In its complexed form acid-sensitive RCbl is protected from degradation in the stomach (Nielsen et al. 2012) and is available for endocytosis.
Literature References
PubMed ID Title Journal Year
22547309 Vitamin B12 transport from food to the body's cells--a sophisticated, multistep pathway

Rasmussen, MR, Moestrup, SK, Andersen, CB, Nielsen, MJ, Nexø, E

Nat Rev Gastroenterol Hepatol 2012
17990953 Haptocorrin in humans

Morkbak, AL, Poulsen, SS, Nexo, E

Clin Chem Lab Med 2007
30777892 A deep proteome and transcriptome abundance atlas of 29 healthy human tissues

Hallström, B, Gagneur, J, Frejno, M, Hahne, H, Asplund, A, Zolg, DP, Eraslan, B, Kuster, B, Schnatbaum, K, Li, LH, Wieland, T, Hopf, T, Meng, C, Zecha, J, Schmidt, T, Ponten, F, Uhlén, M, Wilhelm, M, Wang, D

Mol Syst Biol 2019
Catalyst Activity

cargo receptor ligand activity of TCN1 [extracellular region]

Orthologous Events
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