TCN1 binds correnoids in the circulation

Stable Identifier
R-HSA-3245898
Type
Reaction [transition]
Species
Homo sapiens
Compartment
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The glycoprotein transcobalamin 1 (TCN1 aka haptocorrin, HC, TCI) binds correnoids, biologically inactive analogs of cobalamin (Cbl). The resulting complexes are cleared rapidly from the blood by hepatocytes and excreted in the urine and bile (Kolhouse & Allen 1977). Structural studies by Furger et al. (2013) and Alam et al. (2016) suggest mechanisms for the differential binding of Cbl over other correnoids by TCN2 in contrast to the broad correnoid specificity of TCN1, consistent with a role for the latter in scavenging and mediating the hepatobiliary excretion of corrinoids.

Literature References
PubMed ID Title Journal Year
915005 Absorption, plasma transport, and cellular retention of cobalamin analogues in the rabbit. Evidence for the existence of multiple mechanisms that prevent the absorption and tissue dissemination of naturally occurring cobalamin analogues

Kolhouse, JF, Allen, RH

J Clin Invest 1977
2777761 Structure of the cDNA encoding transcobalamin I, a neutrophil granule protein

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

J. Biol. Chem. 1989
23846701 Structural basis for universal corrinoid recognition by the cobalamin transport protein haptocorrin

Furger, E, Prota, AE, Fischer, E, Schibli, R, Frei, DC

J Biol Chem 2013
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
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Catalyst Activity

molecular sequestering activity of TCN1 [extracellular region]

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