Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: UNIPROT:P47989 (
xanthine oxidase
)
8,633
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
p-
Iodonitrotetrazolium
(2-(4-iodophenyl-3-(4-nitrophenyl)- 5-phenyltetrazolium;
INT
) was reduced to a water-soluble product with an absorbance maxima at about 505 nm (reddish pink) by superoxide anion (O2-.) generated by xanthine/
xanthine oxidase
. The rate of
INT
reduction was linearly related to the
xanthine oxidase
activities, and was inhibited by superoxide dismutase. The soluble product may further be converted to an insoluble product, presumably nonionic formazan, with an absorbance maxima of 490 nm (purplish), under certain conditions, and the rate of the formazan formation depended on pH and protein concentration.
...
PMID:Reduction of iodonitrotetrazolium violet by superoxide radicals. 282 96
The superoxide dismutase mimetic activity of a copper(II) complex with the tetraazamacrocyclic ligand TAAB has been investigated using the xanthin-
xanthine oxidase
system for generation of superoxide. The complex exhibits 50% inhibition of the 3-(4-iodophenyl)-2-(4-nitrophenyl)-5-phenyltetrazolium chloride (
INT
) reduction at the concentration of 0.144 mumol.l-1 (pH 7.8, 25 degrees C). The activity survives in the presence of chelators including EDTA and serum albumin. The enzymatic activity of the complex represents about 3% of that of intact Cu2Zn2SOD.
...
PMID:Superoxide dismutase mimetic activity of macrocyclic Cu(II)-tetraanhydroaminobenzaldehyde (TAAB) complex. 750 91
Light-dependent oxygen reduction in the photosynthetic electron transfer chain, i.e. the Mehler reaction, has been studied using isolated pea thylakoids. The role of the plastoquinone pool in the Mehler reaction was investigated in the presence of dinitrophenyl ether of 2-iodo-4-nitrothymol (DNP-INT), the inhibitor of plastohydroquinone oxidation by cytochrome b6/f complex. Oxygen reduction rate in the presence of DNP-
INT
was higher than in the absence of the inhibitor in low light at pH 6.5 and 7.6, showing that the capacity of the plastoquinone pool to reduce molecular oxygen in this case exceeded that of the entire electron transfer chain. In the presence of DNP-
INT
, appearance of superoxide anion radicals outside thylakoid membrane represented approximately 60% of the total superoxide anion radicals produced. The remaining 40% of the produced superoxide anion radicals was suggested to be trapped by plastohydroquinone molecules within thylakoid membrane, leading to the formation of hydrogen peroxide (H
2
O
2
). To validate the reaction of superoxide anion radical with plastohydroquinone, xanthine/
xanthine oxidase
system was integrated with thylakoid membrane in order to generate superoxide anion radical in close vicinity of plastohydroquinone. Addition of xanthine/
xanthine oxidase
to the thylakoid suspension resulted in a decrease in the reduction level of the plastoquinone pool in the light. The obtained data provide additional clarification of the aspects that the plastoquinone pool is involved in both reduction of oxygen to superoxide anion radicals and reduction of superoxide anion radicals to H
2
O
2
. Significance of the plastoquinone pool involvement in the Mehler reaction for the acclimation of plants to light conditions is discussed.
...
PMID:Involvement of the chloroplast plastoquinone pool in the Mehler reaction. 2825
