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The kinetics and mechanisms of iron removal from human serum transferrin

Thesis/Dissertation ·
OSTI ID:7255532
Iron removal from transferrin by the synthetic catechol sequestering agent, 1,5,10-N,N{prime},N{double prime} - tris(sulfo-2,3-dihydroxybenzoyl)triazadecane, is investigated at pH 7.4 and a range of temperatures and ionic strengths. Biphasic kinetic behavior is observed for iron removal from diferric transferrin and is attributed to kinetic inequivalence between the two sites. The kinetic data are fit to a model which incorporates this assumption. Elucidation of the microscopic rate constants for ion removal from the individual sites is achieved through studies or iron removal from the monoferric transferrins and differic transferrin in which either site is exclusively labeled with radioactive iron. The kinetics of iron release from the ferric transferrins by several types of ligands are carried out to discriminate between proposed mechanisms. The first spectroelectrochemical measurement of the formal reduction potential of iron transferrin is carried out using methyl viologen to mediate electron transfer to the protein. Electrophoretically purified {sup 57}Fe-enriched monoferric and diferric transferrins are studied by Moessbauer spectroscopy. The electronic spectra of the two sites are described by the same set of spin-Hamiltonian parameters.
Research Organization:
California Univ., Berkeley, CA (USA)
OSTI ID:
7255532
Country of Publication:
United States
Language:
English