Isolation of iron-containing superoxide dismutase from Bacteroides fragilis: reconstitution as a Mn-containing enzyme.
Isolation of iron-containing superoxide dismutase from Bacteroides fragilis: reconstitution as a Mn-containing enzyme.
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从脆弱拟杆菌中分离含铁超氧化物歧化酶：重构为含锰酶。
DOI：
10.1016/0003-9861(83)90413-7
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发表时间：
1983
影响因子：
3.9
通讯作者：
Dapper,CH
中科院分区：
文献类型：
--
作者：
Gregory,EM;Dapper,CH
从厌氧菌脆弱拟杆菌中纯化出的超氧化物歧化酶具有明显的同质性。这种名为mr42000的蛋白质是由大小相等的亚基组成的二聚体，通过非共价相互作用连接在一起。金属分析表明，该酶的比活性为1200u /mg，每摩尔二聚体含有18-19个铁原子、0.2个锌原子和<0.05个锰原子。[T. Kirby， J. Blum， I. Kahane， I. Fridovich, 1980]物化学。生物物理学报，2011,551-555)导致酶活性完全丧失。对含硫酸亚铁铵或氯化锰的Tris缓冲液进行透析，可使变性载子蛋白恢复活性。铁重构酶被1mazide抑制，并被h2o2灭活，其方式与天然酶相似。与其他纯化的含锰超氧化物歧化酶相比，锰重组酶能被叠氮化物抑制，但能抵抗h2o2的失活。锰重组蛋白含有~ 1gm原子Mn/mol二聚体。锌离子能有效抑制Mn或Fe对载脂蛋白的重构，并以2-3 g原子/mol二聚体的化学计量量与载脂蛋白结合。
Superoxide dismutase from the anaerobeBacteroides fragilishas been purified to apparent homogeneity. The protein,Mr42,000, is a dimer of equally sized subunits joined by noncovalent interactions. Metal analysis of the native enzyme revealed 18–19 g-atoms Fe, 0.2 g-atoms Zn, and <0.05 g-atoms Mn per mole dimer in a preparation whose specific activity was 1200 U/mg. Exposure of the enzyme to guanidinium chloride plus 8-hydroxyquinoline (T. Kirby, J. Blum, I. Kahane, and I. Fridovich, 1980,Arch. Biochem. Biophys.201, 551–555) resulted in complete loss of enzymatic activity. Activity could be restored by dialysis of the denatured apoprotein against Tris buffer containing either ferrous ammonium sulfate or manganous chloride. The Fe-reconstituted enzyme was inhibited by 1 mmazide and inactivated by H2O2in a manner similar to the native enzyme. Mn-reconstituted enzyme was inhibited by azide but resisted inactivation by H2O2comparable to other purified manganese-containing Superoxide dismutases. The manganese reconstituted protein contained ~1 gm-atom Mn/mol dimer. Zn ion potently inhibited reconstitution of the denatured apoprotein by either Mn or Fe and bound to the protein with a stoichiometry of 2–3 g-atoms/mol dimer.