Smirnoff N
Hatherly Laboratories, School of Biological Sciences, University of Exeter, UK.
Curr Opin Plant Biol. 2000 Jun;3(3):229-35.
Ascorbic acid (vitamin C) is the most abundant antioxidant in plants. Its biosynthetic pathway via GDP-D-mannose and L-galactose, which was proposed only recently, is now supported by molecular genetic evidence from Arabidopsis thaliana and transgenic potato plants. Except for the last step (which is located on the inner mitochondrial membrane) the pathway is cytosolic, sharing GDP-sugar intermediates with cell-wall polysaccharide and glycoprotein synthesis. Ascorbate peroxidase is emerging as a key enzyme in the fine control of H(2)O(2) concentration; its expression being controlled by redox signals and H(2)O(2). Convincing evidence of the involvement of ascorbate in cell division and growth is also accumulating. Its role as a cofactor in the synthesis of cell wall hydroxyproline-rich glycoproteins is one mechanism for this function.
抗坏血酸（维生素C）是植物中含量最丰富的抗氧化剂。其通过GDP-D-甘露糖和L-半乳糖的生物合成途径，虽然是最近才提出的，但现在已得到来自拟南芥和转基因马铃薯植株的分子遗传学证据的支持。除了最后一步（位于线粒体内膜上），该途径存在于细胞质中，与细胞壁多糖和糖蛋白合成共享GDP-糖中间体。抗坏血酸过氧化物酶正在成为精细控制H₂O₂浓度的关键酶；其表达受氧化还原信号和H₂O₂的控制。关于抗坏血酸参与细胞分裂和生长的令人信服的证据也在不断积累。其作为细胞壁富含羟脯氨酸糖蛋白合成中的辅因子的作用是实现这一功能的一种机制。
