Sun Y, Oberley L W, Elwell J H, Sierra-Rivera E
Radiation Research Laboratory, University of Iowa, Iowa City 52242.
Int J Cancer. 1989 Dec 15;44(6):1028-33. doi: 10.1002/ijc.2910440615.
Copper- and zinc-containing superoxide dismutase (CuZnSOD), manganese-containing superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPX, both Se-dependent and Se-independent), and glutathione reductase (GR) were measured in normal, nitrosoguanidine-transformed and SV40-transformed mouse liver cells in culture, as well as in mouse liver homogenates. Enzyme activities were compared on the basis of 3 different endpoints: per mg protein, per mg DNA, and per 10(6) cells. Except for GR, activity of all the measured anti-oxidant enzymes was much higher in vivo than in vitro. All of the anti-oxidant enzyme activities were lower in general in the 2 transformed cell lines than in the in vitro normal cell line, except Cu-ZnSOD, which showed little change. However, MnSOD was the only enzyme which showed lowered activity in both transformed cell lines, no matter what endpoint was used. This finding is in agreement with previous work showing lowered MnSOD activity in tumor cells.
在培养的正常、经亚硝基胍转化和经SV40转化的小鼠肝细胞以及小鼠肝脏匀浆中，对含铜和锌的超氧化物歧化酶（CuZnSOD）、含锰超氧化物歧化酶（MnSOD）、过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GPX，包括硒依赖性和非硒依赖性）以及谷胱甘肽还原酶（GR）进行了测定。基于3个不同的终点对酶活性进行了比较：每毫克蛋白质、每毫克DNA和每10⁶个细胞。除GR外，所有被测抗氧化酶的活性在体内均远高于体外。除Cu-ZnSOD变化不大外，在这两种转化细胞系中，所有抗氧化酶活性总体上均低于体外正常细胞系。然而，无论使用何种终点，MnSOD是唯一在两种转化细胞系中活性均降低的酶。这一发现与之前显示肿瘤细胞中MnSOD活性降低的研究结果一致。
