Role of phosphate and kinetic characteristics of complete iron release from native pig spleen ferritin-Fe

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 diffe...

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Bibliographic Details
Published in:Journal of Protein Chemistry 1999-05, Vol.18 (4), p.497-504
Main Authors: Huang, H Q, Lin, Q M, Kong, B, Zeng, R Y, Qiao, Y H, Chen, C H, Zhang, F Z, Xu, L S
Format: Article
Language:English
Subjects:
Animals
Ascorbic acid
Ascorbic Acid - pharmacology
Dithionite
Dithionite - pharmacology
Ferritin
Ferritins - metabolism
Hogs
Iron
Iron - metabolism
Kinetic equations
Kinetics
Oxidation-Reduction
Phosphates
Phosphates - pharmacology
Spectrophotometry
Spleen
Spleen - chemistry
Swine
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Summary: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.
ISSN:0277-8033
1572-3887
1573-4943
DOI:10.1023/A:1020653028685