Composite organization of the cobalamin binding and cubilin recognition sites of intrinsic factor.

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Fedosov SN, Fedosova NU, Berglund L, Moestrup SK, Nexo E, Petersen TE

Composite organization of the cobalamin binding and cubilin recognition sites of intrinsic factor.

Biochemistry. 2005 Mar 8;44(9):3604-14.

PubMed ID

15736970 [ View in PubMed

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Abstract

Intrinsic factor (IF(50)) is a cobalamin (Cbl)-transporting protein of 50 kDa, which can be cleaved into two fragments: the 30 kDa N-terminal peptide IF(30) and the 20 kDa C-terminal glycopeptide IF(20). Experiments on binding of Cbl to IF(30), IF(20), and IF(50) revealed comparable association rate constants (k(+)(Cbl) = 4 x 10(6), 14 x 10(6), and 26 x 10(6) M(-1) s(-1), respectively), but the equilibrium dissociation constants were essentially different (K(Cbl) = 200 microM, 0.2 microM, and

DrugBank Data that Cites this Article

Drug Transporters

Drug	Transporter	Kind	Organism	Pharmacological Action	Actions
Cyanocobalamin	Cubilin	Protein	Humans	Unknown	Substrate	Details
Cyanocobalamin	Gastric intrinsic factor	Protein	Humans	Unknown	Substrate	Details