Hydrogen peroxide induce modifications of human extracellular superoxide dismutase that results in enzyme inhibition.
Hydrogen peroxide induce modifications of human extracellular superoxide dismutase that results in enzyme inhibition.
复制标题
DOI：
10.1016/j.redox.2012.12.004
复制
发表时间：
2013
期刊：
影响因子：
11.4
通讯作者：
Petersen, Steen V.
中科院分区：
文献类型：
--
作者：
Gottfredsen, Randi H.;Larsen, Ulrike G.;Enghild, Jan J.;Petersen, Steen V.
超氧化物歧化酶（EC-SOD）通过催化超氧化物分解为过氧化氢和分子氧来控制细胞外空间的超氧化物水平。此外，酶在过氧化物酶反应中与过氧化氢反应，已知会破坏酶的活性。在这里，我们证明过氧化物酶反应支持位点特异性键切割。肽图谱和质谱分析表明，Pro112的氧化支持Pro112 - his113肽键的裂解。Ala取代Pro112没有抑制断裂，这表明该位置的氧化断裂是由空间组织决定的，而不是由侧链特异性决定的。被过氧化物酶反应抑制的EC-SOD的主要部分不是碎片化的，而是包含了参与铜配位的组氨酸残基的氧化（His98和His163）。这些氧化很可能支持铜与活性位点的分离，从而导致酶活性的丧失。同源修饰也被描述为细胞内同工酶Cu/Zn-SOD，反映了这些酶内活性位点的几乎相同的结构。我们推测，过氧化物酶活性对EC-SOD的失活在体内调节SOD活性中起作用，因为即使低水平的超氧化物也会允许过氧化物酶反应发生。过氧化氢诱导人EC-SOD氧化修饰。过氧化氢通过氧化靠近活性位点铜的氨基酸残基来抑制EC-SOD。铜的配位球被His98或His163的氧化破坏。蛋白质断裂是由Pro112-His113肽键的断裂介导的。断裂是由Pro112碳上的氢抽离引起的。
Superoxide dismutase (EC-SOD) controls the level of superoxide in the extracellular space by catalyzing the dismutation of superoxide into hydrogen peroxide and molecular oxygen. In addition, the enzyme reacts with hydrogen peroxide in a peroxidase reaction which is known to disrupt enzymatic activity. Here, we show that the peroxidase reaction supports a site-specific bond cleavage. Analyses by peptide mapping and mass spectrometry shows that oxidation of Pro112 supports the cleavage of the Pro112–His113 peptide bond. Substitution of Ala for Pro112 did not inhibit fragmentation, indicating that the oxidative fragmentation at this position is dictated by spatial organization and not by side-chain specificity. The major part of EC-SOD inhibited by the peroxidase reaction was not fragmented but found to encompass oxidations of histidine residues involved in the coordination of copper (His98 and His163). These oxidations are likely to support the dissociation of copper from the active site and thus loss of enzymatic activity. Homologous modifications have also been described for the intracellular isozyme, Cu/Zn-SOD, reflecting the almost identical structures of the active site within these enzymes. We speculate that the inactivation of EC-SOD by peroxidase activity plays a role in regulating SOD activity in vivo, as even low levels of superoxide will allow for the peroxidase reaction to occur. Oxidative modifications of human EC-SOD induced by hydrogen peroxide. ► Hydrogen peroxide inhibits EC-SOD by oxidation of amino acid residues in spatial proximity to the active site copper. ► The coordination sphere of copper is disrupted by the oxidation of His98 or His163. ► Protein fragmentation is mediated by cleavage of the Pro112-His113 peptide bond. ► Fragmentation is induced by hydrogen abstraction on the carbon of Pro112.
登录
查看更多内容
影响因子：
4.8
作者：
Gao, Fei;Koenitzer, Jeffrey R.;Oury, Tim D.
通讯作者：
Oury, Tim D.
影响因子：
4.8
作者：
Deterding, LJ;Ramirez, DC;Tomer, KB
通讯作者：
Tomer, KB
影响因子：
5.6
作者：
Antonyuk, Svetlana V.;Strange, Richard W.;Hasnain, S. Samar
通讯作者：
Hasnain, S. Samar
DOI：
10.4049/jimmunol.1102341
发表时间：
2012-04-01
期刊：
Journal of immunology (Baltimore, Md. : 1950)
影响因子：
--
作者：
Break TJ;Jun S;Indramohan M;Carr KD;Sieve AN;Dory L;Berg RE
通讯作者：
Berg RE
影响因子：
7.4
作者：
Morgan, Philip E.;Pattison, David I.;Davies, Michael J.
通讯作者：
Davies, Michael J.