Related Experiment Video
Updated: Aug 19, 2026

Synthesis of Cationized Magnetoferritin for Ultra-fast Magnetization of Cells
Published on: December 13, 2016
The formation of Fe3+-transferrin-CO3(2-) via the binding and oxidation of Fe2+
Abstract:
This paper examines the reaction pathway in which Fe2+ is bound by apotransferrin and subsequently oxidized by O2 to yield Fe3+-transferrin-CO3(2-). The time course of the reaction follows a curved first order function suggesting somewhat different reactivities of the two transferrin binding sites. The initial velocity of the oxidation reaction follows saturation kinetics with regard to apotransferrin, Fe2+, and NaHCO3. We suggest an equilibrium between these components and Fe2+-transferrin-CO3(2-). The initial velocity is a linear function of O2 concentration. This is consistent with the rate-limiting step of the overall reaction being the oxidation of the Fe2+-transferrin-CO3(2-). A second order rate constant of approximately 4 X 10(3) M-1 s-1 was estimated for the oxidation of Fe2+-transferrin-CO3(2-) by O2. Oxidation by H2O2 is about 30 times faster. The reaction velocity increases with increasing pH between pH 6.0 and 7.5 Fe3+-transferrin-anion complexes are formed by the binding and oxidation of Fe2+ iun the presence of O2 and synergistic anions. The anion is found to have a strong effect on the reaction rate and provides additional evidence for the proposed reaction route. The presence of chelating agents also strongly affects the rate of Fe3+-transferrin-CO3(2-) formation. EDTA and N-(2-hydroxyethyl)ethylenediaminetriacetic acid severely depress the rate, while other chelating reagents have a moderately inhibiting effect. Thioglycolate is found to enhance the reaction by a factor of 9. The formation of a quaternary complex consisting of thioglycolate-Fe2+-transferrin-CO3(2-) is suggested. The results are correlated with an earlier study on the reductive release of iron from transferrin (Kojima, N., and Bates, G. W. (1979) J. Biol. Chem. 254, 8847-8854).
More Related Videos
15:03Synthesis of Functionalized Magnetic Nanoparticles, Their Conjugation with the Siderophore Feroxamine and its Evaluation for Bacteria Detection
Published on: June 16, 2020
09:51TD-DFT Guided Advanced E-Eye Sensing Technique for On-site Quantification of Fe, Cr, F, and As in the Environmental, Biological, and Food Samples
Published on: September 19, 2025
Related Concept Videos
Formation of Complex Ions
Properties of Transition Metals
Metal-Ligand Bonds
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
The Early Endosome: Endocytosis of Transferrin
Complexation Equilibria: Overview
The equilibrium constant of the complexation reaction is represented as the formation constant...
Microbes and Other Elemental Cycles