Daniel Hannelore, Spanier Britta, Kottra Gabor, Weitz Dietmar
Department of Food and Nutrition, Molecular Nutrition Unit, Technical University of Munich, Freising-Weihenstephan, Germany.
Physiology (Bethesda). 2006 Apr;21:93-102. doi: 10.1152/physiol.00054.2005.
Uptake of nutrients into cells is essential to life and occurs in all organisms at the expense of energy. Whereas in most prokaryotic and simple eukaryotic cells electrochemical transmembrane proton gradients provide the central driving force for nutrient uptake, in higher eukaryotes it is more frequently coupled to sodium movement along the transmembrane sodium gradient, occurs via uniport mechanisms driven by the substrate gradient only, or is linked to the countertransport of a similar organic solute. With the cloning of a large number of mammalian nutrient transport proteins, it became obvious that a few "archaic'' transporters that utilize a transmembrane proton gradient for nutrient transport into cells can still be found in mammals. The present review focuses on the electrogenic peptide transporters as the best studied examples of proton-dependent nutrient transporters in mammals and summarizes the most recent findings on their physiological importance. Taking peptide transport as a general phenomenon found in nature, we also include peptide transport mechanisms in bacteria, yeast, invertebrates, and lower vertebrates, which are not that often addressed in physiology journals.
营养物质进入细胞对生命至关重要，并且在所有生物体中都会发生，这需要消耗能量。在大多数原核细胞和简单真核细胞中，跨膜质子电化学梯度为营养物质的摄取提供了核心驱动力，而在高等真核生物中，营养物质摄取更常与钠离子沿跨膜钠离子梯度的移动相偶联，通过仅由底物梯度驱动的单向转运机制发生，或者与类似有机溶质的反向转运相关联。随着大量哺乳动物营养转运蛋白的克隆，很明显在哺乳动物中仍能发现一些利用跨膜质子梯度将营养物质转运到细胞内的“古老”转运蛋白。本综述聚焦于电生性肽转运体，将其作为哺乳动物中研究最充分的质子依赖性营养转运体的例子，并总结了关于它们生理重要性的最新发现。将肽转运视为自然界中普遍存在的现象，我们还纳入了细菌、酵母、无脊椎动物和低等脊椎动物中的肽转运机制，这些在生理学杂志中并不常被提及。
