Li Ze-Qin, Li Jing-Xiao, Zhang Gen-Fa
College of Life Sciences, Beijing Normal University, Beijing, China.
Yi Chuan. 2013 Jan;35(1):45-54. doi: 10.3724/sp.j.1005.2013.00045.
Ascorbate peroxidase (APX), a type I heme peroxidase, catalyzes oxidation of ascorbic acid. It possesses a high degree of specificity to ascorbic acid. APX gene cluster consists of four sub-clusters: the gene clusters of cytosol, chloroplast, mitochondria, and peroxidase. As a key component of hydrogen peroxide detoxification system, the ascorbate-glutathione cycle, APX plays a vital role in the metabolism of H2O2 of plant cells. Studies showed that APX is one of the most important enzymes, which modulate the cellular H2O2 level in redox signaling system. The expression mechanisms of APX isoenzymes are quite complex. Briefly, cytosolic APX is regulated by a variety of signals; two chloroplastic APX isoenzymes are tissue-dependently regulated by alternative splicing. Generated APXs could regulate redox signaling in cells, which further boosts plants tolerance to abiotic stresses. This review focuses on recent advances concerning catalytic prop-erties, physiological function, and gene expressing regulation and abio-stress responding mechanism of APX.
抗坏血酸过氧化物酶（APX）是一种I型血红素过氧化物酶，催化抗坏血酸的氧化。它对抗坏血酸具有高度特异性。APX基因簇由四个子簇组成：胞质溶胶、叶绿体、线粒体和过氧化物酶的基因簇。作为过氧化氢解毒系统（抗坏血酸-谷胱甘肽循环）的关键组成部分，APX在植物细胞H2O2的代谢中起着至关重要的作用。研究表明，APX是调节氧化还原信号系统中细胞H2O2水平的最重要酶之一。APX同工酶的表达机制相当复杂。简而言之，胞质APX受多种信号调节；两种叶绿体APX同工酶通过可变剪接受到组织依赖性调节。产生的APX可以调节细胞内的氧化还原信号，这进一步增强了植物对非生物胁迫的耐受性。本综述重点关注APX的催化特性、生理功能、基因表达调控和非生物胁迫响应机制的最新进展。
