Koningsberger J C, van Asbeck B S, van Faassen E, Wiegman L J, van Hattum J, van Berge Henegouwen G P, Marx J J
Department of Gastroenterology, University Hospital, Utrecht, The Netherlands.
Clin Chim Acta. 1994 Oct 14;230(1):51-61. doi: 10.1016/0009-8981(94)90088-4.
Because superoxide (O2-.) is a mediator of inflammation, Cu,Zn-superoxide dismutase (Cu,Zn-SOD) has been employed as an anti-inflammatory compound. However, Cu,Zn-SOD can increase intra- and extracellular H2O2. This may react with the Cu atom of SOD in a Fenton-type reaction producing the hydroxyl radical (.OH). With a non-physiological concentration of H2O2 (0.8 mmol/l) to stimulate chemiluminescence (CL) at a level < 2 mV, it was observed that the addition of Cu,Zn-SOD (100 micrograms/ml) yielded an increase of 204.7 +/- 78.2 mV (P < 0.05). This increase in CL depended on the concentrations of H2O2 and Cu,Zn-SOD and was only seen with luminol (reacts with O2-. and .OH) but not with lucigenin (reacts with O2-.). No CL was observed when Cu,Zn-SOD was heat inactivated, or when Mn-SOD was used. Dissipators of H2O2, copper chelators and .OH scavengers attenuated this CL. In electron paramagnetic resonance, with the use of the spin-trap dimethylpyrroline-N-oxide (DMPO), it was demonstrated that, in the reaction between H2O2 and Cu,Zn-SOD, .OH was generated. The oxidation of keto-methylthiobutyric acid (KMB) to ethylene, assessed by gas chromatography, demonstrated that H2O2/Cu,Zn-SOD-generated .OH can react with KMB and not only with the SOD molecule itself. We conclude that H2O2 reduces SOD-bound Cu2+ to Cu1+ which, in reaction with H2O2 catalyses its reduction to OH. Whether this 'pro-inflammatory' reaction occurs in vivo remains to be established.
由于超氧阴离子（O2-.）是炎症的介质，铜锌超氧化物歧化酶（Cu,Zn-SOD）已被用作抗炎化合物。然而，Cu,Zn-SOD会增加细胞内和细胞外的过氧化氢（H2O2）。这可能会在芬顿型反应中与SOD的铜原子发生反应，生成羟基自由基（.OH）。在非生理浓度的H2O2（0.8 mmol/l）刺激下，化学发光（CL）水平<2 mV，观察到添加Cu,Zn-SOD（100微克/毫升）会使CL增加204.7±78.2 mV（P<0.05）。这种CL的增加取决于H2O2和Cu,Zn-SOD的浓度，并且仅在鲁米诺（与O2-.和.OH反应）存在时出现，而在光泽精（与O2-.反应）存在时未出现。当Cu,Zn-SOD热失活或使用锰超氧化物歧化酶（Mn-SOD）时，未观察到CL。H2O2的清除剂、铜螯合剂和.OH清除剂会减弱这种CL。在电子顺磁共振中，使用自旋捕获剂二甲基吡咯啉-N-氧化物（DMPO）证明，在H2O2与Cu,Zn-SOD的反应中会生成.OH。通过气相色谱法评估，酮基甲基硫代丁酸（KMB）氧化为乙烯表明，H2O2/Cu,Zn-SOD生成的.OH不仅能与SOD分子本身反应，还能与KMB反应。我们得出结论，H2O2将与SOD结合的Cu2+还原为Cu1+，Cu1+与H2O2反应催化其还原为OH。这种“促炎”反应是否在体内发生仍有待确定。
