The capacity to synthesize vitamin C (ascorbate) is widespread in eukaryotes but is absent from humans. The last step in the biosynthetic pathway involves the conversion of an aldonolactone substrate to ascorbate, a reaction catalyzed by members of an FAD-dependent family of oxidoreductases. Here we demonstrate that both the African trypanosome, Trypanosoma brucei, and the American trypanosome,...

The conversion of fructose-1,6-bisphosphate to glycerate-3-phosphate (PGA) was studied in a reconstituted spinach (Spinacia oleracea L.) chloroplast preparation to determine whether a chloroplast-localized NAB(P)H-oxidizing system (Kow, Smyth, Gibbs 1982 Plant Physiol 69: 72-76 with substrates of ascorbate, NAD(P)H, and H(2)O(2) could serve as a coupling enzyme in the recycling of NAD(P)H. The ...

B etween two and three billion years ago, living things evolved the ability to use oxygen to increase the amount of energy that could be released from carbon-rich molecules. However, these reactions produce harmful molecules called ‘reactive oxygen species’ as byproducts, so antioxidant systems had to be developed in parallel to detoxify them (Noctor and Foyer, 1998; Gest et al., 2013). A compo...

Peroxisomes are subcellular organelles with an essentially oxidative type of metabolism. Like chloroplasts and mitochondria, plant peroxisomes also produce superoxide radicals (O2*(-)) and there are, at least, two sites of superoxide generation: one in the organelle matrix, the generating system being xanthine oxidase, and another site in the peroxisomal membranes dependent on NAD(P)H. In perox...

In this article, we reported the original data obtained by the study of metabolites and enzymes involved in sweet cherry antioxidant system. We measured hydrogen peroxide (H2O2) and malondialdehyde (MDA), which are indicator of oxidative stress. Moreover, we measured the concentration of reduced and oxidized ascorbate and glutathione that are involved in ROS detoxification together with phenoli...

Large changes occur in the ascorbate system during the development of Vicia faba seed and these appear closely related to what are generally considered to be the three stages of embryogenesis. During the first stage, characterized by embryonic cells with high mitotic activity, the ascorbic acid/dehydroascorbic acid ratio is about 7, whereas in the following stage, characterized by rapid cell el...

This report describes a new specific colorimetric procedure for uric acid assay with AutoAnalyzer II and SMA (Technicon) systems, made specific by the application of uricase. Hydrogen preroxide, formed in this reaction, effects the oxidative coupling of 4-aminophenazone and 2,4-dichlorophenol under the catalytic influence of peroxidase. The red dye formed is measured at 505 or 520 nm. A sample ...