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Localization of NADH oxidase on the surface of human polymorphonuclear leukocytes by a new cytochemical method

机译:新的细胞化学方法将NADH氧化酶定位在人多形核白细胞表面

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摘要

The ultrastructural localization of NADH oxidase, a possible enzyme in the increased oxidative activity of polymorphonuclear leukocytes (PMN) during phagocytosis, was studied. A new cytochemical technique for the localization of H2O2, a product of NADH oxidase activity, was developed. Cerous ions, in the presence of peroxide, form an electron- dense precipitate. Resting and phagocytically stimulated PMN were exposed to cerous ions at pH 7.5 to demonstrate sites of NADH- dependent, cyanide-insensitive H2O2 production. Resting PMN exhibites slight activity on the plasma membrane; phagocytizing PMN had extensive deposits of reaction product localized within the phagosome and on the plasma membrane. Peroxide involvement was demonstrated by the inhibitory effect of catalase on cerium precipitation; the surface localization of the enzyme responsible was confirmed by using nonpenetrating inhibitors of enzymatic activity. A correlative study was performed with an NADH-dependent, tetrazolium-reduction system. As with cerium, formazan deposition on the surface of the cell was NADH dependent, cyanide insensitive, and stimulated by phagocytosis. Superoxide dismutase did not inhibit tetrazolium reduction, as observed cytochemically, indicating direct enzymatic dye reduction without superoxide interposition. These findings, combined with oxygen consumption studies on resting and stimulated PMN in the presence or absence of NADH, indicate that NADH oxidase is a surface enzyme in human PMN. It is internalized during phagocytosis and retains its peroxide-generating capacity within the phagocytic vacuole.
机译:研究了NADH氧化酶的超微结构定位,NADH氧化酶是吞噬过程中多形核白细胞(PMN)氧化活性增强的一种可能酶。开发了一种新的细胞化学技术,用于定位NADH氧化酶活性的产物H2O2。在过氧化物的存在下,铈离子形成电子致密的沉淀。静息和受吞噬刺激的PMN在pH 7.5下暴露于铈离子中,以证明NADH依赖的,对氰化物不敏感的H2O2产生的位点。静止的PMN在质膜上表现出轻微的活性;吞噬PMN的反应产物大量沉积物位于吞噬体内和质膜上。过氧化氢酶对铈沉淀的抑制作用证明了过氧化物的参与。通过使用非穿透性的酶活性抑制剂可以确认负责酶的表面定位。用依赖NADH的四唑还原系统进行了相关研究。与铈一样,甲maz在细胞表面的沉积是NADH依赖性的,对氰化物不敏感,并被吞噬作用刺激。如细胞化学观察到的那样,超氧化物歧化酶不抑制四唑还原,这表明酶酶直接还原而无超氧化物插入。这些发现,结合在存在或不存在NADH的情况下对静息和受激PMN的耗氧量研究表明,NADH氧化酶是人PMN中的一种表面酶。它在吞噬过程中被内化,并在吞噬液泡内保留了其过氧化物生成能力。

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