GalLDH

L-半乳糖-1,4-内酯脱氢酶(GalLDH)

L-半乳糖-1,4-内酯脱氢酶(GalLDH)是合成AsA的最后一个酶。GalLDH基因已在许多植物中鉴定,如猕猴桃和栗子玫瑰。GalLDH对L-半乳糖-1,4-内酯具有高度特异性,高浓度的L-半乳糖-1,4-内酯对酶活性有抑制作用。大量研究证实GalLDH基因与AsA含量高度相关。GalLDH mRNA的反义抑制导致GalLDH活性显著下降。然而,尝试通过增加GalLDH的活性来增加AsA含量的方法失败了,主要是因为该蛋白位于线粒体内膜中。据报道,该基因可能通过光诱导来调节AsA含量可能通过光诱导表达或直接影响GalLDH酶活性的光呼吸而产生依赖性的变化。

L-galactose-1,4-lactone dehydrogen-ase(GalLDH)

L-galactose-1,4-lactone dehydrogen-ase(GalLDH) is the last enzyme in the synthesis of AsA.The GalLDH gene has been identified in many plants, such as kiwifruit and chestnut rose. GalLDH was highly specific for L-galactose-1,4-lactone, and the enzymatic activity was inhibited by high concentrations of L-galactose-1,4-lactone. A large number of studies have con firmed that the GalLDH gene and AsA content were highly correlated Antisense suppression of GalLDH mRNA led to a significant decline in the GalLDH activity. However, attempts to increase AsA via GalLDH failed, mainly because this pro tein was located in the inner mitochondria membrane. It has been reported that this gene may be induced by light to regulate AsA content perhaps via light induction of expression or photorespiration-dependent changes directly affecting GalLDH enzyme activity