小分子配位对血红素活性影响的原子-键电负性均衡方法研究  

Investigation on the Effect of Small Coordinated Molecules on the Activity of Heme in Terms of an ABEEM Method

作　　者：崔宝秋[1] 赵东霞[1] 宫利东[1] 

机构地区：[1]辽宁师范大学化学化工学院

出　　处：《化学学报》2008年第14期1627-1631,共5页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.20633050,20403007);高等学校博士学科点专项科研基金(No.20040165001)资助项目

摘　　要：应用原子-键电负性均衡方法,计算了血红素与小分子的配位络合物的电荷分布和Fukui函数.血红素与氧、水、一氧化碳和一氧化氮结合时,铁离子电荷转移到配体原子上.活性中心铁离子的Fukui函数均大于氧和水配体中的配位氧原子,而小于一氧化碳和一氧化氮配体中的配位碳和配位氮原子的Fukui函数.从Fukui函数可以得出,一氧化碳和一氧化氮很难从它们与活性中心血红素结合的配位络合物中解离出来,而氧和水易于从它们与血红素结合的配位络合物中解离出来,进而,血红素可以再与其它配体结合.血红素与KCN和NaN3抑制剂作用时,铁离子的Fukui函数均小于与其配位的碳和氮原子,表明在过氧化氢酶中血红素的活性作用减弱或被抑制.The charge distribution and Fukui function of the coordination complexes of the heme and small molecules were calculated in terms of an atom-bond electronegativity equalization method （ABEEM）. It can be seen that charge transfers from iron ion to the coordinated atoms when the heme and small molecules combine, including O2, H2O, CO and NO. Fukui function of the iron ion is bigger than those of the coordinated oxygen atoms in O2 and H2O, but smaller than those of the coordinated carbon and nitrogen atoms in CO and NO. It can be obtained from the Fukui function that it is difficult for CO and NO to dissociate from the CO and NO coordination complexes of heme, respectively. Whereas it is easy for O2 and H2O to dissociate from the O2 and H2O coordination complexes of heme. Moreover heme is able to combine with other ligands. When the heme combines with the potassium cyanide （KCN） and sodium azide （NAN3） inhibitors, the Fukui function of the iron is smaller than those of the C and N coordinated atoms, and thus the activities of heine in cytohrome c peroxidase are weakened or inhibited.

关 键 词：原子-键电负性均衡方法 血红素 电荷分布 Fukui函数 配位络合物 

分 类 号：R341[医药卫生—基础医学]