Participation of superoxide free radical and Mn2+ in sulfite oxidation

1978 ◽  
Vol 46 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Bunji Inouye ◽  
Mikiko Ikeda ◽  
Tatsuo Ishida ◽  
Masana Ogata ◽  
Jitsuo Akiyama ◽  
...  
Keyword(s):  
Free Radical ◽  
Sulfite Oxidation ◽  
Superoxide Free Radical

Antioxidant Activity of Silk Fibroin Peptide Hydrolyzed by Pancreatin

2014 ◽  
Vol 1081 ◽  
pp. 110-114 ◽  
Author(s):  
Zhen Zhu ◽  
Hua Yin ◽  
Yan An
Keyword(s):  
Antioxidant Activity ◽  
Free Radical ◽  
Nitrogen Content ◽  
Silk Fibroin ◽  
Radical Scavenging ◽  
Amino Nitrogen ◽  
Free Radical Scavenging ◽  
Hydrolysis Process ◽  
Superoxide Free Radical ◽  
Hydrolysis Of

This research adopts the pancreatin hydrolysis of silk fibroin active peptide, evaluate the antioxidant activity of hydrolysates. In the process of hydrolysis of silk fibroin, by measuring the amino nitrogen content of neutral formaldehyde titration method. Find the amino nitrogen content gradually stabilized at around 0.37g/L, and superoxide free radical scavenging rate changing with time fluctuation trend, superoxide free radical scavenging rate to a maximum of 65.03% at 220min.The use of silk fibroin hydrolysis process optimization,reaction time 160min, enzyme concentration4% , substrate concentration 20mg/ml, pH 8, temperature 38°C. The hydrolysis process under the hydrolysate on superoxide radical scavenging rate of 72.73%. The scavenging rate of hydroxyl radical is 47.24%. Red blood cell hemolysis induced by H2O2 inhibition rate was 24.30%.

Superoxide free radical and intracellular calcium mediate Aβ1–42 induced endothelial toxicity

1997 ◽  
Vol 762 (1-2) ◽  
pp. 144-152 ◽  
Author(s):  
Zhiming Suo ◽  
Chunhong Fang ◽  
Fiona Crawford ◽  
Mike Mullan
Keyword(s):  
Free Radical ◽  
Intracellular Calcium ◽  
Superoxide Free Radical

Ethylene Formation by Isolated Chloroplast Lamellae in the Dark

1975 ◽  
Vol 30 (1-2) ◽  
pp. 58-63 ◽  
Author(s):  
Erich Elstner ◽  
Jörg Konze
Keyword(s):  
Heat Treatment ◽  
Superoxide Dismutase ◽  
Free Radical ◽  
Sulfonic Acid ◽  
Ethylene Biosynthesis ◽  
Reactive Species ◽  
Oh Radical ◽  
Ethylene Formation ◽  
Ferredoxin Reductase ◽  
Superoxide Free Radical

Abstract Ethylene Biosynthesis, Chloroplasts, Superoxide Free Radical Isolated chloroplast lamellae from spinach produce ethylene in the dark from methylmercapto-propanal (MMP) or from 2-keto-4-methyl-mercaptobutyrate (KMB) only in the presence of both NADPH and ferredoxin. Anthraquinone-2-sulfonic acid can substitute for ferredoxin. Catalase, superoxide dismutase, ethanol and ascorbate are inhibitors of NADPH-dependent ethylene forma­ tion. Isolated NADP-ferredoxin reductase in the presence of NADPH, ferredoxin and an oxygen reducing factor (ORF, isolated by heat-treatment of chloroplast lamellae) catalyzes ethylene formation from the above substrates in the dark without chloroplast lamellae. From the results it is concluded that chloroplast lamellae in the dark can reduce oxygen monovalently at the expense of NADPH, with the production of the OH-radical as the reactive species responsible for ethylene formation from MMP of KMB.

5-07-39 Batroxobin scavenges superoxide free radical

1997 ◽  
Vol 150 ◽  
pp. S285
Author(s):  
Qizhuan Wu ◽  
Rinying Wang ◽  
Heqiou Bao
Keyword(s):  
Free Radical ◽  
Superoxide Free Radical

Sulfite oxidation by iron-grown cells ofThiobacillus ferrooxidansat pH 3 possibly involves free radicals, iron, and cytochrome oxidase

2001 ◽  
Vol 47 (5) ◽  
pp. 424-430 ◽  
Author(s):  
Lesia Harahuc ◽  
Isamu Suzuki
Keyword(s):  
Free Radical ◽  
Cytochrome Oxidase ◽  
Thiobacillus Ferrooxidans ◽  
Free Radical Scavenger ◽  
Chemical System ◽  
Disulfonic Acid ◽  
Radical Mechanism ◽  
Radical Scavenger ◽  
Sulfite Oxidation ◽  
Free Radical Mechanism

Thiobacillus ferrooxidans cells grown on ferrous iron oxidized sulfite to sulfate at pH 3, possibly by a free radical mechanism involving iron and cytochrome oxidase. A purely chemical system with low concentrations of Fe3+simulated the T. ferrooxidans system. Metal chelators, ethylenediamine tetraacetic acid (EDTA), 4,5-dihydroxy-1-3-benzene disulfonic acid (Tiron), o-phenanthroline, and 2,2'-dipyridyl, inhibited both sulfite oxidation systems, but the T. ferrooxidans system was inhibited only after the initial brief oxygen consumption. EDTA and Tiron, strong chelators of Fe3+, inhibited the oxidation at lower concentrations than o-phenanthroline and 2,2'-dipyridyl, strong chelators of Fe2+. Inhibition of Fe3+-catalyzed sulfite oxidation by EDTA and Tiron was instant, but the inhibition by o-phenanthroline and dipyridyl was briefly delayed, presumably for the reduction of Fe3+to Fe2+. Mannitol, a free radical scavenger, inhibited both systems to the same extent. Cyanide and azide inhibited only the T. ferrooxidans system, suggesting a role of cytochrome oxidase. It is proposed that sulfite is oxidized by a free radical mechanism initiated by Fe3+on the cell surface of T. ferrooxidans. Cytochrome oxidase is possibly involved in the regeneration of Fe3+from Fe2+by the normal Fe2+-oxidizing system of T. ferrooxidans.Key words: Thiobacillus ferrooxidans, sulfite oxidation, iron, free radical, cytochrome oxidase.

Reaotive oxygen generation by azomethine H: a new antimalarial drug

1995 ◽  
Vol 73 (8) ◽  
pp. 1189-1194 ◽  
Author(s):  
Ethel L. B. Novelli ◽  
Assunta M. M. Silva ◽  
Jose L.V.B. Novell F. ◽  
Paulo R. Curi
Keyword(s):  
Superoxide Dismutase ◽  
Free Radical ◽  
Superoxide Radical ◽  
Alanine Transaminase ◽  
Superoxide Dismutase Activity ◽  
Acid Solutions ◽  
Oxygen Generation ◽  
Hydrochloric Acid Solutions ◽  
Superoxide Free Radical ◽  
Important Intermediate

Superoxide radical [Formula: see text] is a free radical that may be involved in various toxic processes. Cu—Zn superoxide dismutase catalyzes the dismutation of the superoxide free radical and protects cells from oxidative damage. A rat bioassay validated for the identification of the toxic effects of azomethine H revealed increased serum activities of amylase, alanine transaminase, and alkaline phosphatase. The lipoperoxide and bilirubin concentrations were also increased in animals that received azomethine H (1 g/kg) from ascorbic or hydrochloric acid solutions. Azomethine H increased Cu–Zn superoxide dismutase activity. This elevation of Cu–Zn superoxide dismutase activity was highest on the 7th day and was at levels comparable with those of control rats from day 60 onwards. Superoxide is an important intermediate in the action and toxicity of azomethine H.Key words: azomethine H, superoxide radical, antimalarial, toxicity.

Rapid determination of superoxide free radical in hepatocellular carcinoma cells by MCE with LIF

2009 ◽  
Vol 30 (6) ◽  
pp. 1077-1083 ◽  
Author(s):  
Xin Liu ◽  
Qingling Li ◽  
Xiaocong Gong ◽  
Hongmin Li ◽  
Zhenzhen Chen ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Free Radical ◽  
Rapid Determination ◽  
Carcinoma Cells ◽  
Hepatocellular Carcinoma Cells ◽  
Superoxide Free Radical

Determination of Superoxide Free Radical Ion and Hydrogen Peroxide as Products of Photosynthetic Oxygen Reduction

1975 ◽  
Vol 30 (1-2) ◽  
pp. 53-57 ◽  
Author(s):  
Erich Elstner ◽  
Claus Stoffer ◽  
Adelheid Heupel
Keyword(s):  
Heat Treatment ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Free Radical ◽  
Oxygen Reduction ◽  
The Other ◽  
Keto Acids ◽  
Superoxide Free Radical ◽  
Photosynthetic Oxygen

Abstract Formation of Nitrite from Hydroxylamine in the presence of illuminated chloroplast lamellae is inhibited by superoxide dismutase but not by catalase, indicating that the superoxide free radical ion and not H2O2 is responsible for the oxidation of hydroxylamine. Decarboxylation of α-keto acids on the other hand is strongly inhibited by catalase but only slightly by superoxide dismutase. Light-dependent hydroxylamine oxidation and decarboxylation of α-keto acids can be used, therefor, as specific and sensitive probes for the determination of either the superoxide free radical ion or hydrogen peroxide, respectively. Photosynthetic oxygen reduction in the presence of ferredoxin, (monitored by the above method) yields both H2O2 and O2·-. The addition of an oxygen reducing factor (ORF, solubilized by heat - treatment of washed chloroplast lamellae) instead of ferredoxin, however, stimulates only the production of H2O2 , while O2·- - formation is not observed. The cooperation of ferredoxin and ORF during photosynthetic oxygen reduction by chloroplast lamellae apparently produces H2O2 not only by dismutation of O2·-, but also by a separate mechanism involving ORF.

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