Holo/apo conversion two-dimensional urea PAGE for speciation of Fe < sup > 3+ < /sup > -bound transferrin in serum

Anal Sci. 2023 Nov 15. doi: 10.1007/s44211-023-00460-z. Online ahead of print.ABSTRACTThis paper presents holo/apo conversion two-dimensional urea polyacrylamide gel electrophoresis (HAC-2D urea PAGE) as a novel method for speciating Fe3+-bound transferrin (Tf) species in biological samples, with a combination of metal ion contaminant sweeping (MICS) technique and Fe3+ detection PAGE. In the HAC-2D urea MICS-PAGE approach, HAC was performed to dissociate all the Fe3+ ions bound to Tf from the Fe-Tf species, during a two-step urea PAGE. Using this method, Fe2-Tf, FeN-Tf, and FeC-Tf (holo-Tf, Fe3+-bound Tf attached to N-lobe, and Fe3+-bound Tf attached C-lobe, respectively) were completely isolated based on the difference in the higher-order structure of Tf, visible as horizontally aligned spots off the diagonal. The Fe3+ ions bound to Tf in each gel fraction were determined using PAGE with a fluorescent probe. Without the MICS technique, which electrophoretically removes all contaminant Fe3+ ions from the gel medium to ensure accurate determination of the Fe3+ concentration, it becomes challenging to precisely measure the distribution of metalloprotein species owing to the contaminants. Finally, the distribution of each Fe-bound Tf in a standard human serum sample was successfully determined by complete separation from large amounts of coexisting proteins, and the free Fe3+ concentration in the serum was estimated.PMID:37966577 | DOI:10.1007/s44211-023-00460-z

Source: Analytical Sciences : the international journal of the Japan Society for Analytical Chemistry - November 15, 2023 Category: Chemistry Authors: Shingo Saito Junko Ishikawa Moe Ono Yuiko Tasaki-Handa Masami Shibukawa Source Type: research