TCN2 binds RCbl in the circulation

Stable Identifier
Reaction [transition]
Homo sapiens
TCII binds RCbl in the circulation
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Transcobalamin (TCN2, TC) is secreted by endothelial cells into plasma where it binds cobalamins (RCbl) and mediates their uptake into cells throughout the body. TCN1 (aka haptocorrin) is also present in the blood and binds RCbl efficiently (Johnston et al. 1989, Quadros et al. 1986, Wuerges et al. 2006), but the TCN1:RCbl complex is not readily taken up from the blood by most cells and and Alam et al. (2016) have suggested that the physiological role of TCN1 is to bind and sequester Cbl-like corenoids to prevent their tissue uptake.
Literature References
PubMed ID Title Journal Year
2777761 Structure of the cDNA encoding transcobalamin I, a neutrophil granule protein

Berliner, N, Johnston, J, Bollekens, J, Allen, RH

J. Biol. Chem. 1989
3782074 Purification and molecular characterization of human transcobalamin II

Rothenberg, SP, Pan, YC, Quadros, EV, Stein, S

J. Biol. Chem. 1986
27411955 Structural basis of transcobalamin recognition by human CD320 receptor

Zenobi, R, Alam, A, Prinz, B, Locher, KP, Bloch, JS, Woo, JS, Chen, F, Schmitz, J, Root, K

Nat Commun 2016
16537422 Structural basis for mammalian vitamin B12 transport by transcobalamin

Randaccio, L, Wuerges, J, Petersen, TE, Geremia, S, Fedosov, SN, Garau, G

Proc. Natl. Acad. Sci. U.S.A. 2006
Catalyst Activity

cargo receptor ligand activity of TCN2 [extracellular region]

Orthologous Events
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