Characterization of the galactono-1,4-lactone dehydrogenase from pepper fruits and its modulation in the ascorbate biosynthesis. Role of nitric oxide

Application of exogenous nitric oxide (NO) gas to pepper fruits provokes enhancements of the ascobate levels and the gene expression and enzyme activity of the galactono-1,4-lactone dehydrogenase (GalLDH). This last enzyme of the of the biosynthetic pathway, which converts galactono-1,4-lactone (GalL) into ascorbate, is characterized by a mitochondrial targeting signal and a transmembrane domain both located at the N-teminus, and is likely to be regulated at transcriptional and post-transcriptional levels by reactive nitrogen species (RNS).113