Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
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Target Concepts:
Gene/Protein
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Query: EC:1.10.3.3 (
ascorbate oxidase
)
778
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Nitroxides were used as models of persistent free radicals to study the antioxidant function of ascorbic acid in the human erythrocyte. It was concluded that: 1) ascorbate and other reductant(s) derived from dehydroascorbic acid (DHA) in the presence of thiols are the only significant reducing agents for nitroxides, 2) glutathione and DHA reduce nitroxides by a process that cannot be inhibited by
ascorbic acid oxidase
, 3) erythrocytes can be depleted of ascorbic acid by exhaustive washing in the presence of membrane-permeable cationic nitroxides such as N,N-dimethylamino-Tempo, 4) ascorbate-depleted cells do not reduce nitroxides; however, nitroxide reduction is restored when the cells are incubated with DHA, 5) reduction of nitroxides in ascorbate-depleted, DHA-treated cells is significantly faster than in buffered solutions of DHA and glutathione, 6) several equivalents of nitroxide are reduced relative to the intracellular ascorbate pool, 7) sustained nitroxide reduction is observed even when most of the intracellular ascorbate is oxidized, 8) spin trapping of oxyradicals in tert-butyl hydroperoxide-treated cells is accelerated with ascorbate depletion and inhibited with ascorbate loading, 9) ascorbate can be quantified within intact cells by analyzing the initial reduction rates of membrane-permeable cationic nitroxides, and 10) DHA-stimulated reduction of cationic nitroxides is slower and less extensive in erythrocytes deficient in
glucose-6-phosphate dehydrogenase
than in normal erythrocytes.
...
PMID:Ascorbate- and dehydroascorbic acid-mediated reduction of free radicals in the human erythrocyte. 199 52
This paper describes the development of a modified electrode for the electrocatalytic oxidation of beta-nicotinamide adenine dinucleotide (beta-NADH) and beta-nicotinamide adenine dinucleotide phosphate (beta-NADPH) using electropolymerised 3,4-dihydroxybenzaldehyde (3,4-DHB). Two voltammetric biosensors using enzyme-immobilised membranes were constructed for the determination of formic acid and glucose-6-phosphate (G6P), respectively. The formic acid biosensor based on the combination of formate dehydrogenase (FDH)-modified membrane with 3,4-DHB-coated glassy carbon electrode is one to two orders more sensitive (LOD, 5.0x10(-5) M) than previously reported electrochemical biosensors. Similarly, lower detection limit (4.0x10(-5) M) for the measurement of G6P was achieved using
glucose-6-phosphate dehydrogenase
(
G6PDH
) in the presence of beta-NADP(+). The interference of uric acid and ascorbate was minimised by incorporating an additional membrane modified with uricase and
ascorbate oxidase
, respectively. The biosensing scheme developed in this study can be adopted universally with a number of dehydrogenases for the detection of different substrates.
...
PMID:Voltammetric biosensors for the determination of formate and glucose-6-phosphate based on the measurement of dehydrogenase-generated NADH and NADPH. 1134
Compared to the control longans, hydrogen peroxide (H
2
O
2
)-treated longans exhibited higher index of pulp breakdown, higher fruit respiration rate, higher activities of pulp phosphohexose isomerase (PGI), succinate dehydrogenase (SDH), cytochrome C oxidase (CCO),
ascorbic acid oxidase
(
AAO
) and polyphenol oxidase (PPO), but lower activity of pulp nicotinamide adenine dinucleotide kinase (NADK). H
2
O
2
-treated longans also exhibited lower total activities of pulp
glucose-6-phosphate dehydrogenase
(G-6-PDH) and 6-phosphogluconate dehydrogenase (6-PGDH), lower levels of pulp NADP(H), but higher levels of pulp NAD(H). These data indicated that H
2
O
2
-stimulated longan pulp breakdown was owing to a decreased proportion of pentose phosphate pathway (PPP), the increased proportions of Embden-Meyerhof-Parnas pathway (EMP), tricarboxylic acid (TCA) cycle and cytochrome pathway (CCP) in total respiratory pathways. These findings further revealed that H
2
O
2
could enhance respiration rate, and thus accelerate pulp breakdown occurrence and shorten the shelf life of longan fruit.
...
PMID:The role of ROS-induced change of respiratory metabolism in pulp breakdown development of longan fruit during storage. 3149 87
