Binding of myeloperoxidase to bacteria: Effect on hydroxyl radical formation and susceptibility to oxidant-mediated killing
Binding of myeloperoxidase to bacteria: Effect on hydroxyl radical formation and susceptibility to oxidant-mediated killing
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DOI：
10.1016/0304-4165(96)00014-1
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发表时间：
1996-08-13
影响因子：
3
通讯作者：
Rosen, GM
中科院分区：
文献类型：
--
作者：
Britigan, BE;Ratcliffe, HR;Rosen, GM
中性粒细胞在摄入微生物病原体时形成超氧阴离子（O-2（-））和过氧化氢（H2 O2），并释放髓过氧化物酶（MPO）。MPO粘附在某些细菌上，催化H2 O2生成HOCl，从而增强H2 O2/O-2（-）杀微生物活性。羟基（HO.），也是H2 O2和O-2（-）杀微生物活性的重要贡献者。MPO降低铁催化的HO。生产，但也会导致HO。通过O-2（-）和HOCl反应生成。我们假设MPO与细菌的结合可以改变HO的大小和位点。生物体暴露于O-2（-）/H2 O2时产生。MPO与大肠杆菌和铜绿假单胞菌的孵育导致MPO与细菌的稳定缔合，这增强了它们对O-2（-）/H2 O2的杀伤的敏感性。在没有MPO预孵育的情况下，E.大肠杆菌对O-2（-）/H2 O2的反应导致铁催化HO，而铜绿假单胞菌对O-2（-）/H2 O2的反应则不然。一代这与两种细菌中氧化还原活性铁的量不同有关。MPO预孵育使HO略有下降。用E. coli，但HO明显增加。与铜绿假单胞菌形成。这可能是由于铁催化的HO减少。生产被增加的铁非依赖性HO抵消。阵MPO预孵育不影响细菌杀死的系统，只产生过氧化氢，排除MPG依赖HO。阵这些数据与MPG衍生HO的可能作用一致。这种酶对细菌的杀伤作用。
Neutrophils form superoxide anion (O-2(-)) and hydrogen peroxide (H2O2) and release myeloperoxidase (MPO) during ingestion of microbial pathogens. MPO, which adheres to some bacteria, catalyzes the formation of HOCl from H2O2, thereby enhancing H2O2/O-2(-) microbicidal activity. Hydroxyl radical (HO.), also is an important contributor to H2O2 and O-2(-) microbicidal activity. MPO decreases iron-catalyzed HO. production but also leads to HO. production through the reaction of O-2(-) and HOCl. We hypothesized that binding of MPO to bacteria could alter the magnitude and site of HO. production upon organism exposure to O-2(-)/H2O2. Incubation of MPO with Escherichia coli and Pseudomonas aeruginosa resulted in stable association of MPO with the bacteria which enhanced their susceptibility to killing by O-2(-)/H2O2. In the absence of MPO preincubation exposure of E. coli, but not P. aeruginosa to O-2(-)/H2O2, led to iron-catalyzed HO. generation. This was associated with different amounts of redox active iron in the two types of bacteria. MPO preincubation slightly decreased HO. detected with E. coli, but markedly increased HO. formation with P. aeruginosa. This likely resulted from decreased iron-catalyzed HO. production counterbalanced by increased iron-independent HO. formation. MPO preincubation did not effect bacterial killing by a system which generated only H2O2, precluding MPG-dependent HO. formation. These data are consistent with a possible role for MPG-derived HO. in the augmentation of bacterial killing by this enzyme.