This enzyme catalyses the final step in the biosynthesis of L-ascorbic acid in higher plants and in nearly all higher animals with the exception of primates and some birds . The enzyme is very specific for its substrate L-galactono-1,4-lactone as D-galactono-gamma-lactone, D-gulono-gamma-lactone, L-gulono-gamma-lactone, D-erythronic-gamma-lactone, D-xylonic-gamma-lactone, L-mannono-gamma-lactone, D-galactonate, D-glucuronate and D-gluconate are not substrates . FAD, NAD+, NADP+ and O2 (cf. EC 1.3.3.12, L-galactonolactone oxidase) cannot act as electron acceptor .
This enzyme catalyses the final step in the biosynthesis of L-ascorbic acid in higher plants and in nearly all higher animals with the exception of primates and some birds [5]. The enzyme is very specific for its substrate L-galactono-1,4-lactone as D-galactono-gamma-lactone, D-gulono-gamma-lactone, L-gulono-gamma-lactone, D-erythronic-gamma-lactone, D-xylonic-gamma-lactone, L-mannono-gamma-lactone, D-galactonate, D-glucuronate and D-gluconate are not substrates [5]. FAD, NAD+, NADP+ and O2 (cf. EC 1.3.3.12, L-galactonolactone oxidase) cannot act as electron acceptor [5].
D-galactono-1,4-lactone, D-gulono-1,4-lactone, L-mannono-1,4-lactone, and D-galacturonic acid are no substrates, molecular oxygen can not serve as efficient electron acceptor for the mutant enzymes
a kinetic and thermodynamic study of the GALDH-cytochrome c interaction and electron-transfer reactions by using laser-flash photolysis and stopped-flow kinetic analysis as well as isothermal titration calorimetry (ITC) and NMR spectroscopy are performed. Results show a transient, highly dynamic GALDH- cytochrome c interaction, similar for all partner redox states
no substrate inhibition with L-gulono-1,4-lactone at concentrations up to 100 mM, D-galactono-1,4-lactone, D-gulono-1,4-lactone, L-mannono-1,4-lactone, and D-galacturonic acid do not inhibit the oxidation of L-galactono-1,4-lactone, no specific inhibition by cations or anions is observed
AtGLDH mRNA level exhibits diurnal change. The level is low in the morning and increases during the day. Its level at 18.00 is about 2fold that in the morning at 6.00. Then the level decreases during the night until dawn of the next day. The diurnal change is regulated by light
at high light, maximal extractable L-GalLDH activity is twice that measured in low light leaves under the same conditions, similarly, intermediate light leaves have 60% higher L-GalLDH activities than low light leaves, however abundance of L-GalLDH mRNA is similar for all light treatments
in a mutant ndufs4 of NADH dehydrogenase [ubiquinone] iron-sulfur protein 4 of Arabidopsis thaliana Col-0, the enzyme is located in the 400 and 450 kDa carbonic anhydrase-containing complexes accumulating in the ndufs4 mutant
the enzyme catalyzes the last step of ascorbate synthesis by oxidising L-galactone-1,4-lactone to ascorbate and transferring two electrons to cytochrome c
the enzyme can play two distinct roles during complex I assembly. First, it can play a structural or stabilizing role for specific assembly intermediates. Second, it can indirectly be essential through providing the ascorbate that might be required during the assembly process. Enzyme GLDH is not required for the early stages of complex I assembly, but it is important for at least one step of the assembly process (transition from the 200 kDa intermediate to the 400 kDa intermediate), it is associated with some assembly intermediates, but it is absent from the mature complex
the chlorophyll fluorescence parameters are significantly higher in enzyme-overexpressing mutants than that in wild type after 14 day high light. The degradation of photosynthetic pigment in wild type is more severe than that in the mutant. GLDH-236OE accumulates more ascorbate, anthocyanins, flavonoids, and phenolics, while wild type accumulates more reactive oxygen species during high light
analysis of the vtc2-1 mutant shows that complex I assembly is not affected in this mutant, while it is affected in the mutant ndufs4 of NADH dehydrogenase [ubiquinone] iron-sulfur protein 4 of Arabidopsis thaliana Col-0, in ndufs4, complex I is not assembled and GLDH is not present in any intermediate larger than 450 kDa. This suggests that the 450 kDa intermediate is a precursor of complex I. Very low amounts of complex I and other assembly intermediates in the gldh mutant, suggesting that the assembly of complex I is not completely arrested, but it is severely impaired in the absence of GLDH
homozygous Arabidopsis thaliana mutant gldhRNAi3-11 plants show approximately 40% of the GLDH activity of wild-type controls and are viable under standard laboratory conditions. Mutant gldhRNAi3-11 plants show about 20% decrease in the contents of reduced ascorbic acid and total ascorbic acid. Partial suppression of GLDH activity confers significant reduction in leaf water loss through decreasing stomatal aperture size in Arabidopsis thaliana, phenotype, overview
three distinct GLDH containing protein complexes of 850, 470, and 420 kDa are discovered using a newly developed in gel GLDH activity assay and immunoblotting. Subunits of the novel 470 and 420 kDa complexes are identified by mass spectrometry. Like the 850-kDa complex, they also include complex I subunits
three distinct GLDH containing protein complexes of 850, 470, and 420 kDa are discovered using a newly developed in gel GLDH activity assay and immunoblotting. Subunits of the novel 470 and 420 kDa complexes are identified by mass spectrometry. Like the 850-kDa complex, they also include complex I subunits
three distinct GLDH containing protein complexes of 850, 470, and 420 kDa are discovered using a newly developed in gel GLDH activity assay and immunoblotting. The 850-kDa complex represents the known smaller version of mitochondrial complex I. GLDH is shown to be attached to the membrane arm of the 850-kDa complex I
analysis of the vtc2-1 mutant shows that complex I assembly is not affected in this mutant, while it is affected in the mutant ndufs4 of NADH dehydrogenase [ubiquinone] iron-sulfur protein 4 of Arabidopsis thaliana Col-0, the enzyme is located in the 400 and 450 kDa carbonic anhydrase-containing complexes accumulating in the ndufs4 mutant. Very low amounts of complex I and other assembly intermediates in the gldh mutant, suggesting that the assembly of complex I is not completely arrested, but it is severely impaired in the absence of GLDH
homozygous Arabidopsis thaliana mutant (gldhRNAi3-11) plants with approximately 40% of the GLDH activity of wild-type controls are developed by RNA interference (three genotypes), and are viable under standard laboratory conditions. Mutant gldhRNAi3-11 plants show about 20% decrease in the contents of reduced ascorbic acid and total ascorbic acid. Partial suppression of GLDH activity in RNAi lines confers significant reduction in leaf water loss through decreasing stomatal aperture size in Arabidopsis thaliana, phenotype, overview
transgenic plant lines with altered levels of mitochondrial alternative oxidase protein have similar levels of L-GalLDH activity whether leaves are measured at low light, or after 4 h exposure to high light
despite limitations on L-GalL synthesis by regulation of early steps in the ascorbic acid synthesis pathway, the regulation of L-GalLDH activity via the interaction of light and respiratory controls is a crucial determinant of the overall ability of leaves to produce and accumulate ascorbic acid
Hervas, M.; Bashir, Q.; Leferink, N.G.; Ferreira, P.; Moreno-Beltran, B.; Westphal, A.H.; Diaz-Moreno, I.; Medina, M.; de la Rosa, M.A.; Ubbink, M.; Navarro, J.A.; van Berkel, W.J.
Communication between (L)-galactono-1,4-lactone dehydrogenase and cytochrome c
Partial suppression of L-galactono-1,4-lactone dehydrogenase causes significant reduction in leaf water loss through decreasing stomatal aperture size in Arabidopsis