KatG from Salmonella typhimurium is a peroxynitritase.
KatG from Salmonella typhimurium is a peroxynitritase.
复制标题
来自鼠伤寒沙门氏菌的 KatG 是一种过氧亚硝酸酶。
DOI：
10.1016/j.febslet.2010.03.029
复制
发表时间：
2010
期刊：
影响因子：
3.5
通讯作者：
McLean S
中科院分区：
文献类型：
--
作者：
McLean S
致病菌引起对氧化和亚硝化应激的保护反应。虽然这种反应通常是不同的，但最近在结核分枝杆菌中报道过氧化氢酶-过氧化物酶（KatG），一种典型的抗过氧化物的防御，也表现出过氧亚硝酸盐酶活性。本文克隆鼠伤寒沙门菌katG基因，对其进行蛋白纯化和鉴定。在pH 7.4, 25°C时，观察到KatG对过氧亚硝酸盐的分解速率增加，二级速率常数为4.2×104M−1s−1。该酶能够将过氧亚硝酸盐对二氢膦胺的氧化降低至83%。考虑到这里展示的过氧亚硝酸盐酶活性，KatG可能在氧化应激解毒中发挥比以前认为的更广泛的作用。
Pathogenic bacteria elicit protective responses to oxidative and nitrosative stresses. Although such responses are generally distinct, it was recently reported in Mycobacterium tuberculosis that catalase–peroxidase (KatG), a classical defence against peroxides, also exhibits peroxynitritase activity. Here, the katG gene from Salmonella Typhimurium was cloned and protein purified and characterised. An increase in the rate of decomposition of peroxynitrite was observed for KatG from the enterobacterium with a second-order rate constant of 4.2×104M−1s−1at pH 7.4, 25°C. This enzyme was able to reduce dihydrorhodamine oxidation by peroxynitrite to ∼83%. Given the peroxynitritase activity demonstrated here it is likely that KatG may play a wider role in the detoxification of oxidative stresses than previously thought.