H-2-uptake activity, spectra, reduction potentials, and kinetics of iron release on the surface of iron core from Azotobacter vinelandii bacterial ferritin

Abstract

Bacterial ferritin from Azotobucter vinelandii (AvBF(o)) has a function in H-2 uptake. The Fe3+ reduction on the surface of the iron core from AvBF(o) is accompanied simultaneously by H-2 uptake, with a maximum activity of H-2 uptake of 450H(2)/AvBF(o). A reduction potential of -402 mV for iron reduction on the surface of the core is found. A shift to the red the protein absorbance peaks ranging from 280 to 290 nm is observed between pH 5 and 9 under 100% H-2 reduction. The reduction potential for iron release becomes negative at a rate of 0.025 mV/Fe2+ released. The kinetics of iron release on the surface of the core is a first-order reaction.