Laboratoire de Physiologie et Biochimie Végétales, Unité Associée Centre National de la Recherche Scientifique 574, Université de Poitiers, 25 rue du Faubourg Saint-Cyprien, 86000 Poitiers, France.
Plant Physiol. 1992 Nov;100(3):1150-6. doi: 10.1104/pp.100.3.1150.
Plasma membrane vesicles (PMVs) were prepared by phase partitioning from microsomal fractions of either sink or source leaves of sugar beet (Beta vulgaris L.). The purity, the internal volume, the sidedness, and the sealingness of PMVs prepared from sink leaves did not differ from those measured with PMVs from source leaves. Yet, in response to an imposed proton motive force, PMVs from source leaves accumulated about 4-fold more sucrose than PMVs from sink leaves. The developmental stage did not affect the uptake of glucose and valine in PMVs prepared from leaf tissues. It was concluded that the sink/source transition is accompanied either by the incorporation into the plasma membrane of leaf cells of proteins mediating proton-sucrose cotransport, or by their activation. N-ethylmaleimide and a polyclonal ascitic fluid directed against the 42-kD region of the plasma membrane containing a putative sucrose carrier inhibited the uptake of sucrose in PMVs from source leaves, but not in PMVs from sink leaves. Sodium dodecyl sulfate gel electrophoresis and western blot suggested that the 42 polypeptide was more abundant in the PMVs from source leaves than in the PMVs from sink leaves.
质膜囊泡（PMV）通过相分离从小麦叶片（Beta vulgaris L.）的胞质体部分制备。从小麦叶片制备的 PMV 的纯度、内部体积、单侧性和密封性与从小麦叶片制备的 PMV 测量值没有差异。然而，在受到质子动力势的影响时，源叶 PMV 比汇叶 PMV 积累的蔗糖多约 4 倍。发育阶段不会影响从小麦叶片组织制备的 PMV 中葡萄糖和缬氨酸的摄取。结论是，汇/源转变伴随着介导质子-蔗糖共转运的蛋白质掺入到叶片细胞的质膜中，或者它们被激活。N-乙基马来酰亚胺和针对质膜中含有推定蔗糖载体的 42-kD 区域的多克隆腹水抑制了从小麦叶片源 PMV 摄取蔗糖，但不抑制从小麦叶片源 PMV 摄取蔗糖。十二烷基硫酸钠凝胶电泳和 Western blot 表明，42 多肽在源叶 PMV 中的丰度高于在汇叶 PMV 中的丰度。
