Battistoni A, Rotilio G
Department of Biology, University of Rome Tor Vergata, Italy.
FEBS Lett. 1995 Oct 30;374(2):199-202. doi: 10.1016/0014-5793(95)01106-o.
We have purified the Cu,Zn superoxide dismutase (CuZnSOD) from the periplasmic space of an Escherichia coli strain unable to synthesize MnSOD and FeSOD. Gel filtration chromatography evidenced that under all the experimental conditions tested the enzyme was monomeric. The catalytic activity of this CuZnSOD was comparable to that of other well characterized dimeric eukaryotic isoenzymes, indicating that a dimeric structure is not essential to ensure enzymatic efficiency. Furthermore the purified enzyme proved to be highly heat-stable and, uniquely among CuZnSODs, protease-sensitive. The latter property may explain the previously described lability of this protein in cell extracts.
我们从一株无法合成锰超氧化物歧化酶（MnSOD）和铁超氧化物歧化酶（FeSOD）的大肠杆菌菌株的周质空间中纯化了铜锌超氧化物歧化酶（CuZnSOD）。凝胶过滤色谱法证明，在所有测试的实验条件下，该酶均为单体。这种CuZnSOD的催化活性与其他特征明确的二聚体真核同工酶相当，表明二聚体结构对于确保酶的效率并非必不可少。此外，纯化后的酶被证明具有高度的热稳定性，并且在CuZnSOD中独一无二的是，它对蛋白酶敏感。后一种特性可能解释了先前描述的这种蛋白质在细胞提取物中的不稳定性。
