Riebe Oliver, Fischer Ralf-Jörg, Bahl Hubert
University of Rostock, Institute of Biological Sciences, Division of Microbiology, Albert-Einstein-Strasse 3, D-18051, Rostock, Germany.
FEBS Lett. 2007 Dec 11;581(29):5605-10. doi: 10.1016/j.febslet.2007.11.008. Epub 2007 Nov 19.
Desulfoferrodoxin (cac2450) of Clostridium acetobutylicum was purified after overexpression in E. coli. In an in vitro assay the enzyme exhibited superoxide reductase activity with rubredoxin (cac2778) of C. acetobutylicum as the proximal electron donor. Rubredoxin was reduced by ferredoxin:NADP(+) reductase from spinach and NADPH. The superoxide anions, generated from dissolved oxygen using Xanthine and Xanthine oxidase, were reduced to hydrogen peroxide. Thus, we assume that desulfoferrodoxin is the key factor in the superoxide reductase dependent part of an alternative pathway for detoxification of reactive oxygen species in this obligate anaerobic bacterium.
丙酮丁醇梭菌的去硫铁氧化还原蛋白（cac2450）在大肠杆菌中过表达后被纯化。在体外测定中，该酶以丙酮丁醇梭菌的红素氧还蛋白（cac2778）作为近端电子供体，表现出超氧化物还原酶活性。红素氧还蛋白被菠菜中的铁氧化还原蛋白：NADP（+）还原酶和NADPH还原。使用黄嘌呤和黄嘌呤氧化酶从溶解氧产生的超氧阴离子被还原为过氧化氢。因此，我们假设去硫铁氧化还原蛋白是这种专性厌氧细菌中活性氧解毒替代途径中超氧化物还原酶依赖性部分的关键因素。
