Ascorbate (vitamin C) is found in high concentrations in the striatum in which it may play a role in behavioral activation. To test this hypothesis, freely behaving rats received bilateral intrastriatal infusions of ascorbate oxidase (AAO) to inactivate extracellular ascorbate. Slow-scan voltammetry was used simultaneously to assess changes in ascorbate and 3,4-dihydroxyphenylacetic acid (DOPAC...

Transgenic tobacco plants expressing the ascorbate oxidase (AAO) gene in sense and antisense orientations, and an Arabidopsis mutant in which the T-DNA was inserted into a putative AAO gene, were used to examine the potential roles of AAO for salt-stress tolerance in plants. AAO activities in the transgenic tobacco plants expressing the gene in sense and antisense orientations were, respectivel...

Abiotic stress and climate change is the major concern for plant growth and crop yield. Abiotic stresses lead to enhanced accumulation of reactive oxygen species (ROS) consequently resulting in cellular damage and major losses in crop yield. One of the major scavengers of ROS is ascorbate (AA) which acts as first line of defense against external oxidants. An enzyme named ascorbate oxidase (AAO)...

Cadmium (Cd) and selenium (Se) could jointly affect plant growth. To investigate the of Se on Cd accumulation in Juglans regia physiological mechanism by which regulates Cd-induced oxidative stress, this study, effects different foliar application doses (0 (Se0), 20 (Se20), 200 (Se200) ?M) J. (variety Xinfeng) seedlings under stress (5 mM) were determined. The results show that exogenous (Se20 ...

A novel biosensor for l-ascorbic acid determination in different beverages was elaborated. The ascorbate oxidase enzyme (AAO) from Cucurbita sp., EC 1.10.3.3, was immobilized on a screen-printed carbon electrode with poly(ethylene glycol) (400) diglycidyl ether (PEGDGE) as a crosslinking agent. The standards and samples were measured first with a blank electrode. An inert protein, bovine serum ...

In this study, it was shown for the first time that l-amino acid oxidase of Pseudomonas sp. AIU813, renamed as l-amino acid oxidase/monooxygenase (l-AAO/MOG), exhibits l-lysine 2-monooxygenase as well as oxidase activity. l-Lysine oxidase activity of l-AAO/MOG was increased in a p-chloromercuribenzoate (p-CMB) concentration-dependent manner to a final level that was five fold higher than that o...

Introduction Ascorbic acid oxidase (AAO) is ;I blue multi-copper oxidase that catalyses the four-electron reduction of dioxygen to water with concomitant one-electron oxidation of tlie reducing organic substrate [ 1 1. Copper-dependent A A O is found only in higher plants 12 I. The enzyme from Cucurbitu pep0 medullosa (green zucchini) is ;I dimer of 14OOOO-M,. containing eight copper ions of th...

Previously, we have found that an insertional inactivation of aao(So), a gene encoding L-amino acid oxidase (LAAO), causes marked repression of the growth of Streptococcus oligofermentans. Here, we found that aao(So) and mutT, a homolog of pyrophosphohydrolase gene of Escherichia coli, constituted an operon. Deletion of either gene did not impair the growth of S. oligofermentans, but double del...

A new procedure has been described for the isolation and purification of ascorbate oxidase from green zucchini squash (Cucurbita pepo meduttosa). The new purification method achieves a more than ZOO-fold purification with about a 14% recovery of the total activity present in the crude juice. The purified enzyme preparations have been found to be homogeneous by the criteria of ultracentrifugal a...