Gene/Protein Disease Symptom Drug Enzyme Compound
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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)

Enzymes and proteins: AO, amine oxidase; and as proposed in reference 3, BSAO, bovine serum AO; SSAO, swine serum AO; SKDAO, swine kidney AO; PSAO, pea seedling AO; APAO, arthrobacter P1AO; MADH, methylamine dehydrogenase; AAO, ascorbic acid oxidase; alpha-AE, alpha-amidating enzyme; Az, azurin; COX, cytochrome c oxidase; CP, ceruloplasmin; DBH, dopamine beta-hydroxylase; GO, galactose oxidase; Hc, hemocyanin; MT, metallotheonein; NIR, nitrite reductase; SOD, superoxide dismutase. Cofactors: Dopa, 3,4 dihydroxyphenylalanine; Topa, 3,4,6 trihydroxyphenyl-alanine; PLP, pyridoxal-phosphate; PQQ, pyrroloquinolinequinone. Reagents: DDC, diethyldithiocarbamate; DMG, diaminoguanidine; DMSA, dimercaptosuccinic acid; NTA, nitrilotriacetic acid. Technique-related: XANES, x-ray absorption near edge spectroscopy; EXAFS, extended x-ray absorption fine structure; ENDOR, electron-nuclear double resonance; ESEEM, electron spin echo envelope modulation; CD, circular dichroism; MCD, magnetic circular dichroism; NMRD, nuclear magnetic resonance dispersion; nqi, nuclear quadrupole interaction; DSC, differential scanning calorimetry.
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PMID:Copper in biological systems. A report from the 6th Manziana Conference, September 23-27, 1990. 175 86

The reactivity with nitric oxide was investigated for a number of type-1, type-2 and type-3 copper proteins azurin from Pseudomonas aeruginosa (type-1 copper); bovine superoxide dismutase, diamine oxidase from pig kidney and galactose oxidase from Dactylium dendroides (type-2 copper); haemocyanin from Helix pomatia (type-3 copper); the blue oxidases ceruloplasmin from pig serum, and ascorbate oxidase from Cucurbita pepo medullosa. Type-1 copper formed complexes with NO in the oxidised state, which complexes were only fully formed at low temperatures and could be photodissociated at 77K. Complex formation led to the disappearance of the EPR signal of type-1 copper and of the optical absorbance band in the 600 nm region. In azurin, photodissociation caused the reappearance of the original 625 nm absorbance band, but in the blue oxidases, a new band with lower intensity was found at 595 nm instead of the original absorbance band at 610 nm. In all cases, the EPR signal of type-1 copper did not return. These results are best explained by the formation of a photolabile type-1 Cu1+-NO+ complex. They also indicate that in the complex formed, the type-1 copper structure is probably not disrupted, and that after illumination, the nitric oxide molecule is still in the near vicinity of the copper atom. Type-2 copper did not react at all with nitric oxide, and type-3 copper formed complexes with nitric oxide in both the oxidised and the reduced state, but photodissociation of these complexes could not be demonstrated.
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PMID:The reaction of nitric oxide with copper proteins and the photodissociation of copper-NO complexes. 282 26

Tyrosinase usually catalyzes the conversion of monophenols to o-diphenols and oxidation of diphenols to the corresponding quinones. However, when 3,4-dihydroxymandelic acid was provided as the substrate, it catalyzed an unusual oxidative decarboxylation reaction generating 3,4-dihydroxybenzaldehyde as the sole product. The identity of the product was confirmed by high-performance liquid chromatography (HPLC) as well as ultraviolet and infrared spectral studies. None of the following enzymes tested catalyzed the new reaction: galactose oxidase, ceruloplasmin, superoxide dismutase, ascorbate oxidase, dopamine beta-hydroxylase, and peroxidase. Phenol oxidase inhibitors such as phenylthiourea, potassium cyanide, and sodium azide inhibited the reaction drastically, suggesting the participation of the active site copper of the enzyme in the catalysis. Mimosine, a well-known competitive inhibitor of tyrosinase, competitively inhibited the new reaction also. 4-Hydroxymandelic acid and 3-methoxy-4-hydroxymandelic acid neither served as substrates nor inhibited the reaction. Putative intermediates such as 3,4-dihydroxybenzyl alcohol and (3,4-dihydroxybenzoyl)formic acid did not accumulate during the reaction. Oxidation to a quinone methide derivative rather than conventional quinone accounts for this unusual oxidative decarboxylation reaction. Earlier from this laboratory, we reported the conversion of 4-alkylcatechols to quinone methides catalyzed by a cuticular phenol oxidase [Sugumaran, M., & Lipke, H. (1983) FEBS Lett. 155, 65-68]. Present studies demonstrate that mushroom tyrosinase will also catalyze quinone methide production with the same active site copper if a suitable substrate such as 3,4-dihydroxymandelic acid is provided.
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PMID:Tyrosinase catalyzes an unusual oxidative decarboxylation of 3,4-dihydroxymandelate. 309 74

The electrochemistry of some copper-containing proteins and enzymes, viz. azurin, galactose oxidase, tyrosinase (catechol oxidase), and the "blue" multicopper oxidases (ascorbate oxidase, bilirubin oxidase, ceruloplasmin, laccase) is reviewed and discussed in conjunction with their basic biochemical and structural characteristics. It is shown that long-range electron transfer between these enzymes and electrodes can be established, and the mechanistic schemes of the DET processes are proposed.
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PMID:Direct electron transfer between copper-containing proteins and electrodes. 1585 24