Peroxynitrite increases the degradation of aconitase and other cellular proteins by proteasome
Peroxynitrite increases the degradation of aconitase and other cellular proteins by proteasome
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DOI：
10.1074/jbc.273.18.10857
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发表时间：
1998-05-01
影响因子：
4.8
通讯作者：
Davies, KJA
中科院分区：
文献类型：
--
作者：
Grune, T;Blasig, IE;Davies, KJA
我们报告说，乌头酸酶暴露于中等浓度的过氧亚硝酸盐，3-morpholinosydnonimine（SIN-1;超氧化物和一氧化氮释放物质），或过氧化氢，抑制酶和增强敏感性蛋白水解消化的分离的20 S蛋白酶体。暴露于更严重的氧化应激水平，从这些相同的代理，造成进一步抑制乌头酸酶的酶活性，但实际上减少其蛋白酶体的蛋白水解分解。应该注意的是，SIN-1分解释放的超氧化物和一氧化氮反应形成稳定的过氧亚硝酸盐通量。S-亚硝基-N-乙酰青霉胺是一种单独释放一氧化氮的化合物，仅引起乌头酸酶活性的少量损失（25%或更少），并且对酶的蛋白水解敏感性没有影响。蛋白酶体似乎也是细胞裂解物中的主要蛋白酶，其可以在乌头酸酶通过暴露于过氧亚硝酸盐、SIN-1或过氧化氢而被氧化修饰后降解乌头酸酶。用蛋白酶体C2亚基起始密码子区的反义寡脱氧核苷酸处理K562细胞几天（使蛋白酶体活性降低50-60%的处理），从K562细胞中分离的细胞裂解物，基本上消除了中度损伤的乌头酸酶的降解增强。其他模型蛋白以及蛋白质的复杂混合物，如细胞裂解物，在适度SIN-1处理后也表现出增强的蛋白水解敏感性。因此，我们得出结论，过氧亚硝酸盐容易与蛋白质反应，过氧亚硝酸盐的温和修饰导致蛋白酶体的选择性识别和降解。
We report that exposure of aconitase to moderate concentrations of peroxynitrite, 3-morpholinosydnonimine (SIN-1; a superoxide-and nitric oxide-liberating substance), or hydrogen peroxide, inhibits the enzyme and enhances susceptibility to proteolytic digestion by the isolated 20 S proteasome. Exposure to more severe levels of oxidative stress, from these same agents, causes further inhibition of the enzymatic activity of aconitase but actually decreases its proteolytic breakdown by proteasome. It should be noted that the superoxide and nitric oxide liberated by SIN-1 decomposition react to form a steady flux of peroxynitrite. S-Nitroso-N-acetylpenicillamine, a compound that liberates nitric oxide alone, causes only a small loss of aconitase activity (25% or less) and has no effect on the proteolytic susceptibility of the enzyme. Proteasome also seems to be the main protease in cell lysates that can degrade aconitase after it has been oxidatively modified by exposure to peroxynitrite, SIN-1, or hydrogen peroxide. Using cell lysates isolated from K562 cells treated for several days with an antisense oligodeoxynucleotide to the initiation codon region of the C2 subunit of proteasome (a treatment which diminishes proteasome activity by 50-60%), the enhanced degradation of moderately damaged aconitase was essentially abolished. Other model proteins as well as complex mixtures of proteins, such as cell lysates, also exhibit enhanced proteolytic susceptibility after moderate SIN-1 treatment. Therefore we conclude that peroxynitrite reacts readily with proteins and that mild modification by peroxynitrite results in selective recognition and degradation by proteasome.