EPR spin-trapping of a myeloperoxidase protein radical.
EPR spin-trapping of a myeloperoxidase protein radical.
复制标题
髓过氧化物酶蛋白自由基的 EPR 自旋捕获。
DOI：
10.1006/bbrc.2000.2396
复制
发表时间：
2000
期刊：
影响因子：
--
通讯作者：
OrtizdeMontellano,PR
中科院分区：
文献类型：
--
作者：
Lardinois,OM;OrtizdeMontellano,PR
髓过氧化物酶（MPO）与H2 O2在自旋捕获DBNBS（3，5-二溴-4-亚硝基苯磺酸）的存在下孵育，导致EPR可检测的部分固定化蛋白质自由基的形成。该自由基仅在MPO和H2 O2存在下形成，表明蛋白质的催化周转是必需的。用链霉蛋白酶处理后的加合物的EPR谱的变化证实了自旋陷阱与蛋白质残基结合。这些结果证实MPO与乳过氧化物酶一样[Lardinois，O. M.，梅齐赫拉德斯基湾F.、和Ortiz de蒙泰拉诺，P. R.（1999）J.Biol.Chem.274，35441-35448]与H2 O2反应，得到蛋白质自由基中间体。蛋白质自由基可能具有催化作用，可能与血红素辅基与蛋白质的共价结合有关，或者可能反映导致酶失活的过程。
Incubation of myeloperoxidase (MPO) with H2O2in the presence of the spin trap DBNBS (3,5-dibromo-4-nitrosobenzenesulfonic acid) results in the EPR-detectable formation of a partially immobilized protein radical. The radical was only formed in the presence of both MPO and H2O2, indicating that catalytic turnover of the protein is required. The changes in the EPR spectrum of the adduct upon treatment with pronase confirm that the spin trap is bound to a protein residue. These results establish that MPO, like lactoperoxidase [Lardinois, O. M., Medzihradszky, K. F., and Ortiz de Montellano, P. R. (1999) J. Biol. Chem. 274, 35441–35448], reacts with H2O2to give a protein radical intermediate. The protein radical may have a catalytic role, may be related to covalent binding of the prosthetic heme group to the protein, or may reflect a process that leads to inactivation of the enzyme.