Holo-transferrin

The Fe +/ + reduction potentials for holo-transferrin have been difficult to determine because of their low values and the need to take account of the dissociation of Fe(II) from diferrous-transferrin. This has been estimated from the association constant for Fe(II) binding to transferrin at pH 7.4, 10 M, which yields reduction potentials < —500 mV at pH 7.4 for the C-terminal and N-termtnal sites of human serum transferrin, and probably more negative potentials at the lower pH present in the endosome where iron is released. ... 

Zhao, Y.Y., Mandal, R. and Li, F.X., Intact human holo-transferrin interaction with oxaliplatin. Rapid Commun. Mass Spectrom., 19(14), 1956-1962 (2005). 

Figure 7.13 The transferrin to cell cycle HOLO-TF, diferric transferrin TFR, transferrin receptor DMT1, divalent metal transporter. (From Andrews, 2000. Reproduced by permission of Nature Reviews Genetics.)...

After 1 hour of treatment, fluorescent transferrin can be localized in early endosomes and the endosomal-recycling compartment, whereas the cholera toxin B-subunit distinctly traffics to the trans-golgi network of living cells. In cells treated with holo-cholera toxin comprising the B-subunit and the catalytic A-subunit, the toxin would traffic further to the endoplasmic reticulum, which would enable the release of the toxic A-subunit into the cytoplasm. 

FIGURE 7.18 The transferrin to cell cycle. HOLO-TF diferric transferrin TfR, transferrin receptor DMTl, divalent metal transporter. 

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