Search results for "OXIDASE"
showing 10 items of 927 documents
Interaction of sodium, lithium, caesium, and potassium ions with ascorbyl radicals.
1987
Abstract The influence of the concentration of sodium, lithium , caesium, and potassium ions as well as of the ionic strength of the solutions used on the dismutation rate of ascorbyl radicals has been investigated. While the dismutation rate was not influenced by Li+, it decreased, however, with increasing concentrations of the other ions investigated. The largest effect was obtained with Na+. This change in dismutation rate indicates a stabilizing effect on ascorbyl radical by these ions.
Immuno-fluorescence cytochemistry on thin frozen sections of human substantia nigra for staining of monoamine oxidase A and monoamine oxidase B: a pi…
1990
Immunofluorescence cytochemistry on thin frozen sections of human substantia nigra for staining of MAO-A and MAO-B revealed that only about 10% of the melanin-containing neurons are positive for MAO-A, while they are substantially free of MAO-B.
pH control of the production of recombinant glucose oxidase in Aspergillus nidulans.
2004
Aims: Recombinant Aspergillus nidulans sVAL040, capable of synthesizing and secreting glucose oxidase derived from Aspergillus niger was used to study the influence of pH and carbon source on enzyme production. Methods and Results: Glucose oxidase gene (goxC) was expressed under transcriptional regulation by using the promoter of A. nidulans xlnB gene (encoding an acidic xylanase). A maximum specific glucose oxidase activity of approx. 10 U mg−1 protein and a maximum volumetric productivity of 29·9 U l−1 h−1 were obtained at pH 5·5, after 80 h of growth by using xylose as inducer. Enzyme volumetric productivity increased when xylans were used instead of xylose; however, specific glucose o…
Glutathione peroxidase-1 in health and disease: from molecular mechanisms to therapeutic opportunities.
2011
Reactive oxygen species, such as superoxide and hydrogen peroxide, are generated in all cells by mitochondrial and enzymatic sources. Left unchecked, these reactive species can cause oxidative damage to DNA, proteins, and membrane lipids. Glutathione peroxidase-1 (GPx-1) is an intracellular antioxidant enzyme that enzymatically reduces hydrogen peroxide to water to limit its harmful effects. Certain reactive oxygen species, such as hydrogen peroxide, are also essential for growth factor-mediated signal transduction, mitochondrial function, and maintenance of normal thiol redox-balance. Thus, by limiting hydrogen peroxide accumulation, GPx-1 also modulates these processes. This review explor…
γ-Glutamylcysteine detoxifies reactive oxygen species by acting as glutathione peroxidase-1 cofactor
2012
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 3.0 Unported License.
Glutathione peroxidase 1 activity dictates the sensitivity of glioblastoma cells to oxidative stress.
2012
The high intratumoral and intertumoral heterogeneity of glioblastoma (GBM) leads to resistance to different therapies, and hence, selecting an effective therapy is very challenging. We hypothesized that the antioxidant enzyme status is a significant feature of GBM heterogeneity. The most important reactive oxygen/nitrogen species (ROS/RNS) detoxification mechanisms include superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx). Expression and activity of these enzymes and the cellular response to induced oxidative stress were systematically analyzed and compared between GBM cells and nontransformed glial cells of both human and murine origin. Regardless of cell type or speci…
Lipid Rafts in Higher Plant Cells
2004
A large body of evidence from the past decade supports the existence of functional microdomains in membranes of animal and yeast cells, which play important roles in protein sorting, signal transduction, or infection by pathogens. They are based on the dynamic clustering of sphingolipids and cholesterol or ergosterol and are characterized by their insolubility, at low temperature, in nonionic detergents. Here we show that similar microdomains also exist in plant plasma membrane isolated from both tobacco leaves and BY2 cells. Tobacco lipid rafts were found to be greatly enriched in a sphingolipid, identified as glycosylceramide, as well as in a mixture of stigmasterol, sitosterol, 24-methyl…
Isolation and partial characterization of a cytochrome-o complex from chromatophores of the photosynthetic bacterium Rhodospirillum rubrum FR1.
1989
A cytochrome-o complex was isolated from chromatophores of photoheterotrophically grown Rhodospirillum rubrum FR1. The enzyme was extracted with the non-denaturating detergent taurodeoxycholate and subsequently purified by sucrose-density-gradient centrifugation and gel-permeation HPLC. The complex contains two types of cytochromes, one of them cytochrome o, and two copper atoms. It catalyzes the reduction of molecular oxygen, when N,N,N',N'-tetramethyl-p-phenylenediamine or ubiquinol 10 are offered as electron donors. The oxidase activity is inhibited by cyanide, carbon monoxide and 2-heptyl-2-hydroxyquinoline N-oxide. The molecular mass of the protein is 136 +/- 15 kDa. The subunit analys…
Molecular size and net charge of pathogenesis-related enzymes from barley (Hordeum vulgare L., v. Karat) infected withDrechslera teres f. teres (Sacc…
1998
Molecular size and net charge of isoforms of pathogenesis-related (PR) chitinase, beta-1,3-glucanase and peroxidase were studied in uninfected barley (Hordeum vulgare L., v. Karat) leaves and in barley leaves infected with the pathogenic fungus Drechslera teres f. teres (Sacch.) Shoem. Molecular characteristics were determined by time-dependent polyacrylamide gradient gel electrophoresis under native conditions and by applying an extended version of the computer program MOL-MASS (Rothe, G. M., Weidmann, H., Electrophoresis 1991, 12, 703-709). Uninfected barley leaves contained predominantly one peroxidase isozyme but also three very weak peroxidases. Activities of all of these three peroxid…
Nitric Oxide: Biological Synthesis and Functions
2012
The pluripotent gaseous messenger molecule nitric oxide (NO) controls vital functions such as neurotransmission or vascular tone (via activation of soluble guanylyl cyclase), gene transcription, mRNA translation (via iron-responsive elements), and post-translational modifications of proteins (via ADP-ribosylation). In higher concentrations, NO is capable of destroying parasites and tumor cells by inhibiting iron-containing enzymes or directly interacting with the DNA of these cells. In view of this multitude of functions of NO, it is important to understand the mechanisms by which cells accomplish and regulate the production of this molecule. In mammals, three isozymes of NO synthase (NOS; …