HL-60 cells differentiated with DMSO increased their rates of uptake of ascorbate when they were activated with PMA. The rates observed after this activation were essentially the same as those with dehydroascorbic acid as the original transport substrate. The effect of activation was sensitive to the antioxidant enzymes superoxide dismutase and catalase. When ascorbate was oxidized in situ by c...

Cell suspensions of Campylobacter fetus subsp. intestinalis grown microaerophilically in complex media consumed oxygen in the presence of formate, succinate, and DL-lactate, and membranes had the corresponding dehydrogenase activities. The cells and membranes also had ascorbate-N,N,N',N'-tetramethyl-p-phenylenediamine oxidase activity which was cyanide sensitive. The fumarate reductase activity...

The functionalized conducting polymer (CP) of 5, 2':5', 2' '-terthiophene-3'-carboxylic acid on a platinum microelectrode was prepared through the electropolymerization process using cyclic voltammetry and was used as a substrate for the immobilization of enzymes. The nanoparticles of the CP were obtained at a high scan rate in the cyclic voltammetric experiment. A needle-type amperometric glut...

A unique A/T-rich sequence (5'-AAAAAGTAAAAA-GTAAAAAAGTAAAAAG-3), referred to as the AGTA repeat, is found in the silencer region of the pumpkin ascorbate oxidase gene. A cDNA for protein (AOBP) that binds to the AGTA repeat was isolated from pumpkin by the southwestern method. The AOBP protein has a new class of zinc/DNA-binding domain named Dof/MOA domain that is highly conserved in many plant...

Ascorbate oxidase (AO, EC 1.10.3.3) catalyzes the oxidation of ascorbate (AsA) to yield water. AO over-expressing plants are prone to ozone and salt stresses, whereas lower expression apparently confers resistance to unfavorable environmental conditions. Previous studies have suggested a role for AO as a regulator of oxygen content in photosynthetic tissues. For the first time we show here that...

A comprehensive survey of the interaction of the copper proteins and oxygen is presented including a correlation of structure, function, and other properties of the known copper oxidases and of hemocyanin. The origin of their blue color and the structure of copper complexes and copper proteins are related to the oxidation state of copper ion and relevant electronic transitions probably arising ...

The pacific oyster (Crassostrea gigas), a good model for studying biomineralization and coastal environmental change, was used to study the expression of cuproproteins after waterborne Cu exposure (3 μg Cu L(-1)) similarly to the Arcachon Bay aquatic environment. Cuproproteins in oyster cytosols were analyzed by gel electrophoresis (non-denaturing PAGE and SDS 2-DE), laser ablation inductively ...

In this procedure, oxalate oxidase (EC 1.2.3.4) immobilized in a continuous-flow system is used to determine oxalate in urine. The hydrogen peroxide formed from oxalate is detected by use of a color reaction with peroxidase (EC 1.11.1.7), 3-methyl-2-benzothiazoline hydrazine, and N,N-dimethylalanine. However, urine contains an oxalate oxidase inhibitor, which cannot be removed by heating, ion-e...

The unmediated electrochemistry of two large Cu-containing proteins, ascorbate oxidase and laccase, was investigated by direct-current cyclic voltammetry. Rapid heterogeneous electron transfer was achieved in the absence of promoters or mediators by trapping a small amount of protein within a solid, electrochemically inert, tributylmethyl phosphonium chloride membrane coating a gold electrode. ...