Fei Y J, Kanai Y, Nussberger S, Ganapathy V, Leibach F H, Romero M F, Singh S K, Boron W F, Hediger M A
Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts.
Nature. 1994 Apr 7;368(6471):563-6. doi: 10.1038/368563a0.
In mammals, active transport of organic solutes across plasma membranes was thought to be primarily driven by the Na+ gradient. Here we report the cloning and functional characterization of a H(+)-coupled transporter of oligopeptides and peptide-derived antibiotics from rabbit small intestine. This new protein, named PepT1, displays an unusually broad substrate specificity. PepT1-mediated uptake is electrogenic, independent of extracellular Na+, K+ and Cl-, and of membrane potential. PepT1 messenger RNA was found in intestine, kidney and liver and in small amounts in brain. In the intestine, the PepT1 pathway constitutes a major mechanism for absorption of the products of protein digestion. To our knowledge, the PepT1 primary structure is the first reported for a proton-coupled organic solute transporter in vertebrates and represents an interesting evolutionary link between prokaryotic H(+)-coupled and vertebrate Na(+)-coupled transporters of organic solutes.
在哺乳动物中，有机溶质跨质膜的主动转运被认为主要由Na+梯度驱动。在此，我们报告了从兔小肠中克隆出的一种H(+)偶联的寡肽和肽衍生抗生素转运体及其功能特性。这种新蛋白质名为PepT1，具有异常广泛的底物特异性。PepT1介导的摄取是生电的，不依赖细胞外的Na+、K+和Cl-以及膜电位。在小肠、肾脏、肝脏中发现了PepT1信使核糖核酸，在大脑中也有少量存在。在小肠中，PepT1途径构成了蛋白质消化产物吸收的主要机制。据我们所知，PepT1的一级结构是脊椎动物中首次报道的质子偶联有机溶质转运体，代表了原核生物H(+)偶联和脊椎动物Na(+)偶联有机溶质转运体之间有趣的进化联系。
