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首页> 美国卫生研究院文献>Infection and Immunity >The CuZn superoxide dismutases of Aspergillus flavus Aspergillus niger Aspergillus nidulans and Aspergillus terreus: purification and biochemical comparison with the Aspergillus fumigatus CuZn superoxide dismutase.
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The CuZn superoxide dismutases of Aspergillus flavus Aspergillus niger Aspergillus nidulans and Aspergillus terreus: purification and biochemical comparison with the Aspergillus fumigatus CuZn superoxide dismutase.

机译：黄曲霉黑曲霉构巢曲霉和土曲霉的铜锌超氧化物歧化酶：与烟曲霉铜锌超氧化物歧化酶的纯化和生化比较。

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Cu,Zn superoxide dismutases (SODs) have been purified to homogeneity from Aspergillus flavus and A. niger, which are significant causative agents of aspergillosis, and from A. nidulans and A. terreus, which are much rarer causative agents of disease, using a combination of isoelectric focusing and gel filtration fast protein liquid chromatography. The purified enzymes have been compared with the previously described SOD from the most important pathogen in the genus, A. fumigatus (M. D. Holdom, R. J. Hay, and A. J. Hamilton, Free Radical Res. 22:519-531, 1995). The N-terminal amino acid sequences of the four newly purified enzymes were almost identical and demonstrated homology to known Cu,Zn SODs from a range of organisms including that from the previously described SOD from A. fumigatus. SOD activity was detectable in the culture filtrates of all species, and intracellular Cu,Zn SOD activity as a proportion of total protein was highest in early-log-phase cultures. The specific activities of the purified enzymes were similar, and all four of the newly described enzymes were inhibited by potassium cyanide and diethyldithiocarbamate, known Cu,Zn SOD inhibitors. Sodium azide and o-phenanthroline demonstrated inhibition at concentrations from 5 to 30 mM, and EDTA also exhibited a varying degree of inhibition of SOD activity. However, there were differences in the nonreduced molecular masses, the reduced molecular masses, and the isoelectric points of the four newly described SODs and the A. fumigatus enzyme; these varied from 55 to 123 kDa, 17.5 to 19.5 kDa, and 5.0 to 5.9, respectively. Of particular note was the observation that the A. fumigatus enzyme was thermostable compared with the SODs from the other species; in addition, the A.fiumigatus enzyme retained all of its activity at 37 degrees C relative to 20 degrees C, whereas the SODs of A. nidulans and A. terreus lost significant activity at the higher temperature. Aspergillus Cu,Zn SOD plays a hypothetical role in the avoidance of oxidative killing mechanisms, and our data suggest that the thermotolerant A. fumigatus Cu,Zn SOD would be more effective in such a protective system than, for example, the equivalent enzyme from the more rarely pathogenic A. nidulans.
机译：铜，锌超氧化物歧化酶（SODs）已通过使用等电聚焦和凝胶过滤结合快速蛋白质液相色谱。已经将纯化的酶与先前描述的来自烟曲霉属中最重要病原体的SOD进行了比较（M.D.Holdom，R.J.Hay和A.J.Hamilton，Free Radical Res.22：519-531，1995）。四种新纯化的酶的N末端氨基酸序列几乎相同，并与来自多种生物的已知Cu，Zn SOD同源，包括先前描述的来自烟曲霉的SOD。在所有物种的培养滤液中均可检测到SOD活性，在早期对数期培养中，细胞内Cu，Zn SOD活性占总蛋白的比例最高。纯化的酶的比活性相似，并且所有四种新近描述的酶均被已知的铜，锌超氧化物歧化酶抑制剂氰化钾和二乙基二硫代氨基甲酸酯抑制。叠氮化钠和邻菲咯啉在5至30 mM的浓度下表现出抑制作用，而EDTA也表现出不同程度的对SOD活性的抑制作用。但是，四种新描述的SOD和烟曲霉的未还原分子量，还原分子量和等电点存在差异。它们分别从55到123 kDa，17.5到19.5 kDa和5.0到5.9不等。特别值得注意的是，与其他物种的SOD相比，烟曲霉酶具有热稳定性。此外，相对于20摄氏度，A.fiumigatus酶在37摄氏度下保留了全部活性，而构巢曲霉和土曲霉的SOD在较高温度下失去了明显的活性。曲霉菌的铜，锌超氧化物歧化酶在避免氧化杀伤机制中起着假设的作用，我们的数据表明，在这种保护系统中，耐高温的烟曲霉铜，锌超氧化物歧化酶比从中提取的同等酶更有效。很少有病原性构巢曲霉。

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