细菌铁蛋白氧化还原特性及电极活性的研究

STUDIES ON REDOX CHARACTERISTICS AND ELECTRODE ACTIVITY OF BACTERIAL FERRITIN

棕色固氮菌细菌铁蛋白能直接快速地从金属铂电极上得到电子或提供电子给铂电极。经－６００ｍＶ（相对于ＮＨＥ）还原电位处理后，还原态细菌铁蛋白在可见光谱区中（３８０－５８０ｎｍ）所呈现的整体吸收光谱强度明显高于氧化态细菌铁蛋白的吸收光谱强度。经氯化钴处理后的细菌铁蛋白表现出较弱的电极活性及释放铁的速率明显下降。此外，细菌铁蛋白在体外模拟棕色固氮菌整体细胞内的微量氧环境体系中仍有氢还原现象，因而推测细菌铁蛋白在该菌体内也能进行吸氢反应。

Bacterial ferritin from Azotobacter vinelandii can directly and quickly pick reduction electrons from a metal platinum electrode or provide electrons to it. The spectral absorbance intensity in the visible spectrum (380-580 nm) of reduced bacterial ferritin after treated by the potential at -600 mV vs. NHE is evidently higher than that of the oxidized it. Being treated by cobalt chloride, the ferritin exhibits weak activity to the electrode and its rate for iron release decreases evidently. It suggests that on the protein shell of bacterial ferritin exist a structure of partial electron tunnel consisting of mixed composition of heme-Fe2+ and heme-Co2+. H2-uptake phenomenon of the bacterial ferritin is still found in an analogy system of micro-oxygen environment of entire cell Azotobacter vinelandii in vitro, which indicates that the H2-uptake reaction can be carried out by the ferritin within the cell. The bacterial ferritin is a protein which possesses characteristics of H2-uptake hydrogenase-like activity.