Role of Phosphate and Kinetic Characteristics of Complete Iron Release from Native Pig Spleen Ferritin-Fe

Abstract

The kinetics for complete iron release showing biphasic behavior from pig spleen ferritin-Fe (PSFF) was measured by spectrophotometry. The native core within the PSFF shell consisted of 1682 hydroxide Fe3+ and 13 phosphate molecules. Inhibition kinetics for complete iron release was measure by differential spectrophotometry in the presence of phosphate; the process was clearly divided into two phases involving a first-order reaction at an increasing rate of 46.5 Fe3+/PSFF/min on the surface of the iron core and a zero-order reaction at a decreasing rate of 6.67 Fe3+/PSFF/min inside the core. The kinetic equation [C(PSFF-Fe3+)max - C(PSFF-Fe3+)t](1/2) = Tmax - Tt gives the transition time between the two rates and represents the complex kinetic characteristics. The rate was directly accelerated twofold by a mixed reducer of dithionite and ascorbic acid. These results suggest that the channel of the PSFF shell may carry out multiple functions for iron metabolism and storage and that the phosphate strongly affects the rate of iron release.

Bio-inspired protein–gold nanoconstruct with core–void–shell structure: beyond a chemo drug carrier

“…Ammonium tetrachloroaurate(III) (NH 4 AuCl 4 , 99.99% (metals basis)) was purchased from Alfa Aesar China Co., Ltd. For control experiments, citrate-stabilized Au particles, with an average size of $3.5 nm, were prepared according to the method reported by Nikhil R. Jana et al 53 Apoferritin was prepared from ferritin by a reductive dissolution procedure, 16 while ferritin was obtained according to the methods described previously. 54,55 All the other chemicals used were of analytical grade and commercially available unless otherwise stated.…”

Iron Incorporation into Escherichia coli Dps Gives Rise to a Ferritin-like Microcrystalline Core

“…It is of interest to compare the present findings on Dps with the literature data involving classical ferritins and dithionite (Table I). Two kinetic phases have been observed in pig spleen ferritin, a fast, first order reaction for iron release from the surface of the core and a slower zero order reaction involving iron inside the core (29). In Azotobacter vinelandii hemecontaining ferritin a similar biphasic reduction process takes place, albeit with different characteristics, since both phases depend on dithionite concentration in a complex manner.…”

Comparison of the kinetics of iron release from a marine (Trichodesmium erythraeum) Dps protein and mammalian ferritin in the presence and absence of ligands

“…Reduction of Fe(III) by ascorbic acid results in a faster initial mobilization of Fe from the Dps core. The two kinetic phases observed at high concentrations of DFB and ascorbate have been reported in E. coli Dps, pig spleen ferritin, and Azotobacter vinelandii bacterioferritin [15,25,26]. Different Fe populations within the protein cage, or heterogeneity in the iron core are thought to be responsible for the two kinetic phases.…”