Suzuki Y J, Mizuno M, Packer L
Department of Molecular & Cell Biology, University of California, Berkeley 94720, USA.
Biochem Biophys Res Commun. 1995 May 16;210(2):537-41. doi: 10.1006/bbrc.1995.1693.
H2O2 has been proposed as a second messenger involved in cell signaling for NF-kappa B activation. In the present study, this hypothesis was tested by transiently overexpressing catalase, a specific scavenger of H2O2, in COS-1 cells. A mammalian expression vector was constructed by incorporating catalase gene from pCAT10 clone into the unique EcoRI site of the pSG5 vector which contains the SV-40 promoter. Transient transfection of the catalase expression vector by the DEAE-dextran method led to a four-fold increase in catalase activity and catalase content as detected by immunoblot analysis. This level of increase was detected in both nuclear/mitochondrial- and cytosolic/microsomal fractions. Overexpression of catalase, however, did not block TNF- or PMA-induced NF-kappa B activation. These results weaken the hypothesis that H2O2 is a second messenger for TNF- and PMA-signaling for NF-kappa B activation.
过氧化氢（H2O2）被认为是参与核因子-κB（NF-κB）激活的细胞信号传导的第二信使。在本研究中，通过在COS-1细胞中瞬时过表达过氧化氢酶（一种H2O2的特异性清除剂）来验证这一假设。通过将来自pCAT10克隆的过氧化氢酶基因整合到含有SV-40启动子的pSG5载体的独特EcoRI位点，构建了一个哺乳动物表达载体。通过DEAE-葡聚糖法对过氧化氢酶表达载体进行瞬时转染，导致免疫印迹分析检测到过氧化氢酶活性和过氧化氢酶含量增加了四倍。在核/线粒体和胞质/微粒体部分均检测到这种增加水平。然而，过氧化氢酶的过表达并未阻断肿瘤坏死因子（TNF）或佛波酯（PMA）诱导的NF-κB激活。这些结果削弱了H2O2是TNF和PMA信号传导导致NF-κB激活的第二信使这一假设。
