Human eosinophilic peroxidase: role in bactericidal activity.
Human eosinophilic peroxidase: role in bactericidal activity.
复制标题
人嗜酸性过氧化物酶：在杀菌活性中的作用。
作者：
R. Migler;L. Dechatelet;D. Bass
过氧化物酶存在于中性粒细胞和嗜酸性粒细胞中，被认为通过在氯化物存在下氨基酸的脱羧作用或在碘化物存在下蛋白质的碘化作用参与白细胞的杀菌活性。我们检查了纯化的中性粒细胞和嗜酸性粒细胞的声波提取物中的这些活性，并将它们与提取物杀死细菌的能力联系起来。与嗜中性粒细胞相反，嗜酸性粒细胞无细胞系统不能使L丙氨酸-1-14C脱羧。嗜中性粒细胞过氧化物酶的脱羧作用取决于过氧化氢浓度，在高水平下具有抑制作用。过氧化物酶介导的脱羧显示出最佳pH值为4.5，并且取决于所用缓冲液的类型，按照增加活性的顺序，N-（2-乙酰氨基）-亚氨基二乙酸（ADA）、Tris-马来酸盐、磷酸钠和乙酸钠。碘化作用（以将25 L转化为三氯乙酸可沉淀形式的能力来测量）在静息嗜酸性粒细胞中比在静息嗜中性粒细胞中更大。两种类型的白细胞在吞噬酵母聚糖后显示出增加的碘化能力。当碘化物用作卤化物时，嗜酸性粒细胞和中性粒细胞无细胞制剂显示出杀菌活性，如通过金黄色葡萄球菌和大肠杆菌活力的降低所测量的。相反，用氯化物作为卤化物，只有中性粒细胞系统可以有效地杀死这两种生物。这一发现与嗜酸性过氧化物酶不能催化脱羧反应的观察结果一致，并且表明这种机制在杀菌活性中的重要性。
Peroxidase, present in both neutrophils and eosinophils, is thought to be involved in the bactericidal activity of leukocytes, through either the decarboxylation of amino acids in the presence of chloride or the iodination of proteins in the presence of iodide. We examined these activities in sonic extracts of purified neutrophils and eosinophils and related them to the ability of the extracts to kill bacteria. In contrast to the neutrophil, the eosinophil cell-free system is unable to decarboxylate Lalanine-1 -‘4C. Decarboxylation by the neutrophil peroxidase is dependent on the hydrogen peroxide concentration, with inhibition at high levels. Peroxidase-mediated decarboxylation showed a pH optimum at 4.5 and was dependent on the type of buffer employed, in order of increasing activity, N-(2-acetamido)-iminodiacetic acid (ADA), Tris-maleate, sodium phosphate, and sodium acetate. lodination, measured as the ability to convert ‘25l into a trichloroacetic acid-precipitable form, was greater in resting eosinophils than in resting neutrophils. Both leukocyte types show increased iodinating ability upon phagocytosis of zymosan. When iodide was used as the halide, eosinophil and neutrophil cell-free preparations showed bactericidal activity as measured by the reduction in viability of Staph yiococcus aureus and Escherichia coil. In contrast, with chloride as the halide only the neutrophil system could effectively kill both organisms. This finding is in agreement with the observation that eosinophilic peroxidase is unable to catalyze the decarboxylation reaction, and it suggests the importance of this mechanism in bactericidal activity.