‘新红星’苹果果实蔗糖合酶的活性及亚细胞定位

 在‘新红星’苹果果实发育过程中, 伴随果糖、葡萄糖和蔗糖的积累, 蔗糖合酶的分解活性逐渐下降, 而合成活性逐渐升高。苹果果实的蔗糖合酶由分子量为90 kD 的亚基组成, 其免疫信号强度随发育进程而增加。蔗糖合酶主要定位于果肉细胞的细胞质中, 发育中后期该酶的分布密度有一定增加。综合结果认为, 蔗糖合酶调控发育早期蔗糖的降解和发育后期蔗糖的积累。

Activity and Subcellular Localization of Sucrose Synthase in ‘ Starkrimson' Apple during Fruit Development

The experiment conducted with `Starkrimson' apple fruit showed that the degradation activity of sucrose synthase declined gradually with the accumulation of fructose, glucose and sucrose during fruit development. However, the synthesis activity of sucrose synthase decreased during the early stage of fruit development and then increased significantly during the late development stage. Western blotting assay of sucrose synthase detected the presence of a 90kD peptide and the intensity of immuno-signal increased with fruit developing. On the other hand, the results of immunogold electron-microscopy assay showed that sucrose synthase was mainly located in the cytoplasm of apple flesh cell and few immunogold particles were found on cell wall or in vacuole. The results also indicated that the quantity of sucrose synthase increased with fruit development and was consistent with the results of Western blotting. So it is suggested that the degradation and synthesis of sucrose in apple fruit may be modulated by sucrose synthase. Fructose may act as sugar signal and modulate the activity of sucrose synthase.