Weber A, Servaites J C, Geiger D R, Kofler H, Hille D, Gröner F, Hebbeker U, Flügge U I
Universität zu Köln, Lehrstuhl Botanik II, Gyrhofstrasse 15, D-50931 Cologne, Germany.
Plant Cell. 2000 May;12(5):787-802. doi: 10.1105/tpc.12.5.787.
During photosynthesis, part of the fixed carbon is directed into the synthesis of transitory starch, which serves as an intermediate carbon storage facility in chloroplasts. This transitory starch is mobilized during the night. Increasing evidence indicates that the main route of starch breakdown proceeds by way of hydrolytic enzymes and results in glucose formation. This pathway requires a glucose translocator to mediate the export of glucose from the chloroplasts. We have reexamined the kinetic properties of the plastidic glucose translocator and, using a differential labeling procedure, have identified the glucose translocator as a component of the inner envelope membrane. Peptide sequence information derived from this protein was used to isolate cDNA clones encoding a putative plastidic glucose translocator from spinach, potato, tobacco, Arabidopsis, and maize. We also present the molecular characterization of a candidate for a hexose transporter of the plastid envelope membrane. This transporter, initially characterized more than 20 years ago, is closely related to the mammalian glucose transporter GLUT family and differs from all other plant hexose transporters that have been characterized to date.
在光合作用期间，部分固定碳被用于合成暂存淀粉，暂存淀粉作为叶绿体中的一种中间碳储存物质。这种暂存淀粉在夜间被调动。越来越多的证据表明，淀粉分解的主要途径是通过水解酶进行的，并导致葡萄糖的形成。该途径需要一种葡萄糖转运体来介导葡萄糖从叶绿体中输出。我们重新研究了质体葡萄糖转运体的动力学特性，并使用差异标记法确定葡萄糖转运体是内膜的一个组成部分。从该蛋白质获得的肽序列信息被用于从菠菜、马铃薯、烟草、拟南芥和玉米中分离编码假定质体葡萄糖转运体的cDNA克隆。我们还展示了质体包膜膜己糖转运体候选物的分子特征。这种转运体在20多年前首次被表征，与哺乳动物葡萄糖转运体GLUT家族密切相关，并且与迄今已表征的所有其他植物己糖转运体不同。
