Abstract
NADH-glutamate dehydrogease (GDH) is located in mitochondria and catalyzes both reactions for the amination of 2-oxoglutalate and the deamination of glutamate. Physiological function of this enzyme has long been unknown.
In addition to the previously isolated two cDNAs for GDH (OsGDH1 and OsGDH3), another cDNA OsGDH2 was identified. RT-PCR showed OsGDH3 expression was not detectable in any organs. This is in contrast to other OsGDH genes, which were expressed in all organs tested. Immunolocalization analysis showed OsGDH protein in developing organs is mainly accumulated in the phloem elements. This was in contrast to the localization of cyt c oxidase protein, a mitochondrial marker, which was detected in all cell types. GDH protein content was stably detected in the leaf blade during senescence. Analysis with the transgenic rice overexpressing NADH-glutamate synthase is now in progress.
