The oxidation of a number of thioethers, namely methyl phenyl sulphide (1), ethyl phenyl sulphide (2), isopropyl phenyl sulphide (3), n-propyl phenyl sulphide (4), p-chlorophenyl methyl sulphide (5), p-nitrophenyl methyl sulphide (6) and methyl naphthalene sulphide (7), by recombinant pea cytosolic ascorbate peroxidase (rAPX) and a site-directed variant of rAPX in which the distal tryptophan 41...

Mixed quantum mechanics/molecular mechanics (QM/MM) methods offer a valuable computational tool for understanding the electron transfer pathway in protein-substrate interactions and protein-protein complexes. These hybrid methods are capable of solving the Schrödinger equation on a small subset of the protein, the quantum region, describing its electronic structure under the polarization effect...

drought is considered as one of the most important limiting factors for oil seed canola plant(brassica napus l.) growth and productivity in iran. on the basis of root and shoot dry weight asaffected by water stress exerted by peg 6000, out of 9 canola cultivars, a relatively tolerant (cv. aghaii)and a sensitive cultivar (cv. po4) were selected. their responses to low water potential with respec...

Ascorbic acid has numerous and diverse roles in plant metabolism. We have used the vtc-1 mutant of Arabidopsis, which is deficient in ascorbate biosynthesis, to investigate the role of ascorbate concentration in growth, regulation of photosynthesis, and control of the partitioning of antioxidative enyzmes. The mutant possessed 70% less ascorbate in the leaves compared with the wild type. This l...

The aim of this study was to characterize the effect of decreased 2-cysteine peroxiredoxin (2-CP) on the leaf anti-oxidative system in Arabidopsis. At three stages of leaf development, two lines of transgenic Arabidopsis mutants with decreased contents of chloroplast 2-CP were compared with wild type and a control line transformed with an empty vector. Glutathione contents and redox state were ...

We evaluated the efficacies of five treatment procedures for eliminating ascorbate interference in the enzymatic determination of urinary oxalate. Aliquots of urine samples, containing different amounts of added ascorbate and oxalate, were individually subjected to ferric chloride, sodium nitrite, sodium periodate, charcoal, or ascorbate oxidase treatment to eliminate ascorbate interference. Ox...

Strong antioxidant activity of Pelargonium graveolens is well known. The question addressed in this study was whether different concentrations of exogenous ascorbic acid (AsA) and iron (Fe) were able to influence antioxidant activity and total phenol content (TPC) of geranium. Thus, three levels of Fe (0, 20 and 40 µM) and three levels of AsA (0, 1 and 2 mM) in nutrient solution were c...

After SO(2) has entered leaves of spinach (Spinacia oleracea) through open stomata and been hydrated in the aqueous phase of cell walls, the sulfite formed can be oxidized to sulfate by an apoplastic peroxidase that is normally involved in phenol oxidation. The oxidation of sulfite is competitive with the oxidation of phenolics. During sulfite oxidation, the peroxidase is inhibited. In the abse...

common vetch ( vicia sativa l.) an annual forage, belonging to the fabaceae family is one of the highly cultivated forage legumes in iran. drought stress is a serious adverse factor that limits plant growth and productivity, inducing a range of physiological as well as biochemical responses in plants. it may also lead to generation of oxygen activated species which in turn result in cell destru...