title: Enhanced activity of galactono-1,4-lactone dehydrogenase and ascorbate-glutathione cycle in mitochondria from complex III deficient Arabidopsis.
abstract: The mitochondrial antioxidant homeostasis was investigated in Arabidopsis ppr40-1 mutant, which presents a block of electron flow at complex III. The activity of the ascorbate biosynthetic enzyme, L-galactono-1,4-lactone dehydrogenase (EC 1.3.2.3) (GLDH) was elevated in mitochondria isolated from mutant plants. In addition increased activities of the enzymes of Foyer-Halliwell-Asada cycle and elevated glutathione (GSH) level were observed in the mutant mitochondria. Lower ascorbate and ascorbate plus dehydroascorbate contents were detected at both cellular and mitochondrial level. Moreover, the more oxidized mitochondrial redox status of ascorbate in the ppr40-1 mutant indicated that neither the enhanced activity of GLDH nor Foyer-Halliwell-Asada cycle could compensate for the enhanced ascorbate consumption in the absence of a functional respiratory chain.
authors: Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Temesvári Körút 62, H-6726 Szeged, Hungary.
authors: Laura
authors: L
authors: Zsigmond
authors: Bálint
authors: B
authors: Tomasskovics
authors: Veronika
authors: V
authors: Deák
authors: Gábor
authors: G
authors: Rigó
authors: László
authors: L
authors: Szabados
authors: Gábor
authors: G
authors: Bánhegyi
authors: András
authors: A
authors: Szarka