摘要
棕色固氮菌细菌铁蛋白(Bacterial ferritin ofAzotobacter vinelandii,AvBF)分子结构由蛋白壳、铁核和横跨蛋白壳的电子隧道组成.细菌铁蛋白由24个相同类型的亚基组成,其分子量略高于魟鱼肝铁蛋白(Liver ferritin ofDasyatis aka-jei,DALF).电泳纯的AvBF在可见光谱区内呈现出4个特征吸收峰,波长分别位于414(α峰),525(β峰),555(S峰)和585(未知)nm.经Na2S2O4还原后,其AvBF在紫外可见区内的整体吸收峰强度明显增高.经物理铂金电极还原后,AvBF的α特征吸收峰(414 nm)强度随着控制还原电位降低(-200,-400,-600 mV vs NHE)而增强.动力学研究表明,在弱碱(pH8.0)条件下,AvBF和DALF均以二分之一级反应动力学方式释放铁,均未表现出释放铁速率转换行为,认为AvBF和DALF的释放铁速率和铁蛋白蛋白壳的柔性调节速率处于同步进行状态,使铁蛋白释放铁的过程符合二分之一级反应动力学规律.
Molecular structure from bacterial ferritin of Azotobacter vinelandii （AvBF） consists of protein shell, iron core and electron tunnel across its shell. AvBF is composed of 24 subunits with single types,but its molecular weight is a little higher than that of Liver ferritin of Dasyatis akajei（DALF）. AvBF with electrophoresis purity showed four characteristic absorbance peaks （CAPs） in visible spectral region,which their wavelength were 414（α）,525（β） ,555 （S）,585 （unknown） nm. The whole absorbanee intensity in AvBF enhanced evidently while reduced with excess Na2S2O4. The intensity of CAPs at 414 nm（a peak） increased going with the controlled potential to shift to negative at -200,-400,-600 mV vs NHE, respectively,in response to reduce with physical electrode. The kinetics showed that both AvBF and DALF released its iron as a law of half-order in the absence of rate exchange,indicating that both proteins carried out the same rate of iron release while both protein engaged in the similar regulation rate of protein shell itself,which resulted in the kinetic laws of iron release both ferritins followed a half-order reaction.
出处
《厦门大学学报（自然科学版）》
CAS
CSCD
北大核心
2006年第5期717-721,共5页
Journal of Xiamen University：Natural Science
基金
国家自然科学基金(30470372)资助
关键词
细菌铁蛋白
棕色固氮菌
电子光谱
释放铁
动力学
bacterial ferritin
Azotobacter vinelandii
electron spectrum
iron release kinetics
