title: Studies on the heme and H2-uptake reaction from Azotobacter vinelandii bacterial ferritin.
abstract: Bacterial ferritin of Azotobacter vinelandii (AvBF) is directly able to pick electrons up for iron release from or transfer them for storage to a platinum electrode in the absence of mediator or other reducer. The ferritin containing the structure of heme-Co2+ in part shows weakened activity to electrode and decreases the rate of iron release greatly. A reversible reduction process of the ferritin is observed by the spectral change regularly ranging from 310 to 260 nm under mixed gases containing 98% H2 and 2% to O2. The activity of nitrogen fixation from the whole cell of A. vinelandii increases greatly by H2 reduction with potentials ranging from -397 to -425 mV vs. NHE, indicating two important roles of H2-uptake reaction of the ferritin in increasing activity of nitrogen fixation and in supplying iron to synthesize nitrogenase.
authors.affiliation: Department of Biology, Xiamen University, China.
authors.forename: H Q
authors.initials: HQ
authors.lastname: Huang
authors.forename: Q M
authors.initials: QM
authors.lastname: Lin
authors.forename: F Z
authors.initials: FZ
authors.lastname: Zhang
authors.forename: C H
authors.initials: CH
authors.lastname: Chen
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: Z
authors.initials: Z
authors.lastname: Chen
mesh_terms: D016948:Azotobacter vinelandii / Q000737:chemistry* / Q000378:metabolism; D004566:Electrodes; D004579:Electron Transport; D005293:Ferritins / Q000737:chemistry* / Q000302:isolation & purification; D006418:Heme / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry; D007700:Kinetics; D009586:Nitrogen Fixation; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D006418:Heme; D006859:Hydrogen; D005293:Ferritins; D007501:Iron; D010100:Oxygen