摘要
采用ESR、CD谱和荧光光谱研究了pH=6.3时六次甲基四胺-HCl缓冲溶液中LaCl_3和TbCl_3与Cu(Zn)-SOD的配位作用和结构。Cu(Zn)-SOD可增强Tb^(3+)的荧光发射,Tb^(3+)与Cu(Zn)-SOD有多个配位位置,其中有2个强结合位点,La^(3+)与Tb^(3+)可竞争Cu(Zn)…SOD上相同结合位点,77K下La^(3+)与Tb^(3+)使Cu(Zn)-SOD的Cu^(2+)活性中心的配位环境由菱形对称结构向轴对称结构转变,使Cu(Zn)-SOD的局部结构变松散,但对SOD酶活性基本无影响,表明稀土离子主要与酶蛋白分子中的酸性氨基酸羧基配位,对酶蛋白二级结构仅产生微弱扰动,对活性中心空间结构影响较小,基本不影响Cu(Zn)-SOD酶活性。
The interactions of lanthanium trichloride and terbium trichloride with bovine blood Cu (Zn)-superoxide dismutase [Cu(Zn)-SOD] in the aqueous solution of hexam-ethylenetetramine buffer (pH = 6. 3) have been'studied by using fluorescece, CD and ESR spectra. The results indicated that rare earth ions were coordinated to the carboxyl groups of acidic amino acid residues which were far from active center of the Cu(Zn)-SOD molecule and only lightly disturbed the secondary structure of the enzyme protien, and made the coordination structure of enzyme-bound Cu2+ come from the rhombchedron to the axial shape at 77 K and the activity of Cu(Zn)-SOD enzyme was not nearly changed at room temperature.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
1995年第7期993-996,共4页
Chemical Journal of Chinese Universities
基金
国家攀登计划基金
