Construction of a ferritin reactor: an efficient means for trapping various heavy metal ions in flowing seawater

Heavy metal detoxification by recombinant ferritin from Apostichopus japonicus

Ferritin fromApostichopus japonicasshowed better ability in heavy metal detoxification than horse spleen ferritin.

Purification, electrophoretic behavior, and kinetics of iron release of liver ferritin of Dasyatis akajei

From the liver of fish Dasyatis akajei, ferritin has been isolated by thermal denaturation and ammonium sulfate fractionation and then further purified by anion exchange chromatography and gel exclusion chromatography. The molecular weight of the liver ferritin of D. akajei (DALF) was measured to be 400 kDa by PAGE. Moreover, SDS-PAGE experimentation indicates that protein shell of DALF consists of the H and L subunits with molecular weight of 18 and 13 kDa, respectively. Using isoelectric focusing with pH ranging from 5.0 to 6.0, the ferritin purified by the PAGE exhibited three bands with different pI values in the gel slab. Diameters of the protein shell and iron core were also investigated by transmission electron microscope and determined to be 10-12 nm and 5-8 nm, respectively. A kinetic study of DALF reveals that the rate of self-regulation of the protein shell rather than the complex surface of the iron core plays an important role in forming a process for iron release with mixed orders.

Kinetics of iron release from pig spleen ferritin with bare platinum electrode reduction

Several anaerobic electrochemical cells were employed to study the kinetics of iron release from pig spleen ferritin (PSF) at a bare platinum electrode. Controlled potential microcoulometry (CPM) is the principal technology used to investigate the kinetics in the absence of a mediator. A kinetic study of iron release by microcoulometry has revealed that ferritin undergoes direct electron transfer at the electrode in the absence of a mediator, indicating that ferritin is an electroactive protein. Several experiments failed to show that alpha'alpha-bipyridyl has the capacity to reduce hydrolyzed Fe(3+) within the ferritin core after it has been reduced by the electrode at -600 mV vs. NHE in the absence of mediator. PSF is known to bind heme to generate a hemeoprotein, named pig spleen hemeoferritin (PSF(ho)). The rate of iron release is accelerated by the heme binding to PSF(ho) without the need for small mediators. Under similar conditions, two kinetic processes for iron release from PSF and bacterial ferritin of Azoaobacter vinelandii (AvBF) were studied and both fit a zero-order law. In addition, the rate of iron release in PSF can be accelerated two-fold by a specific reduction system consisting of ascorbic acid (AA) and the bare platinum electrode at -600 mV. However, this kinetic process does not follow zero-, half-, first, or second-order rate laws. A model is proposed to explain a mechanism of direct electron transfer between ferritin and the electrode is derived to describe the kinetics of iron release.