Schrenzel J, Serrander L, Bánfi B, Nüsse O, Fouyouzi R, Lew D P, Demaurex N, Krause K H
Division of Infectious Diseases, Department of Medicine, University Hospital, Geneva, Switzerland.
Nature. 1998 Apr 16;392(6677):734-7. doi: 10.1038/33725.
Electron transport across biological membranes is a well-known feature of bacteria, mitochondria and chloroplasts, where it provides motive forces for vectorial transport processes. In contrast, electron transport is generally not found in the plasma membrane of eukaryotic cells, possibly because it would interfere with electric processes at the plasma membrane. An exception is provided by the phagocyte NADPH oxidase, which generates superoxide (O2.-) through electron transfer from cytosolic NADPH to extracellular oxygen. The enzyme is essential for host defence, and patients with chronic granulomatous disease, who lack the functional enzyme, suffer from severe infections. It has been suggested that electron transfer by the NADPH oxidase might be electrogenic. Here we demonstrate, using the whole-cell patch-clamp technique, the generation of electron currents by the NADPH oxidase in human eosinophil granulocytes. The currents were absent in granulocytes of sufferers of chronic granulomatous disease and under conditions of low oxygen. Generation of electron currents across the plasma membrane of eukaryotic cells has not been observed previously and might be-independently of the generation of superoxide-a physiologically relevant function of the phagocyte NADPH oxidase.
电子跨生物膜运输是细菌、线粒体和叶绿体的一个众所周知的特征，在这些细胞器中，它为向量运输过程提供动力。相比之下，真核细胞质膜中一般不存在电子运输，这可能是因为它会干扰质膜上的电过程。吞噬细胞NADPH氧化酶是一个例外，它通过将胞质NADPH的电子转移到细胞外氧来产生超氧化物（O2.-）。该酶对宿主防御至关重要，缺乏功能性该酶的慢性肉芽肿病患者会遭受严重感染。有人提出，NADPH氧化酶的电子转移可能是生电的。在这里，我们使用全细胞膜片钳技术证明了人嗜酸性粒细胞中NADPH氧化酶能产生电子电流。慢性肉芽肿病患者的粒细胞以及在低氧条件下均不存在这种电流。此前尚未观察到真核细胞质膜上产生电子电流的现象，这可能是吞噬细胞NADPH氧化酶一种与超氧化物产生无关的生理相关功能。
