When intracellular iron concentration is low, an iron regulatory protein inhibits the synthesis of apoferritin and promotes the synthesis of transferrin receptor.
The small amount of circulating ferritin is mostly apoferritin that contains little iron.
Vekilov and Siu-Tung Yau at the University of Alabama in Huntsville used an atomic force microscope to view the protein apoferritin as it crystallizes.
To overcome these challenges, Vekilov and Yau waited for apoferritin clusters to approach the bottom of a glass cell where the researchers already had placed an apoferritin crystal as a docking point.
They found that all of these clusters had roughly the same shape--a flat layer of apoferritin molecules with a few more molecules on top.
The equation was derived from the migration distances of both protein-coated gold particles (diameters, 21.1 and 29.2 nm, respectively) and from the migration distances of the thyroglobulin dimer (23.6 nm), thyroglobulin (17.0 nm), and
apoferritin (12.2 nm).
Thyroglobulin (T-1126), apoferritin (A-3641), and dithiothreitol (D-0632) were purchased from Sigma.
The average particle diameters of the calibrator LDL samples were estimated by GGE from a linear calibration curve of the logarithm of the diameter vs the migration distance, with apoferritin (12.2 nm), thyroglobulin (17.0 nn), and thyroglobulin dimer (23.6 nm) as calibrators of known diameter.
Marker proteins, e.g., apoferritin and thyroglobulin, and calibrated latex beads are frequently used in GGE for calibration.
Effects of H and L human
apoferritins on lipid peroxidation in vitro.