PROMOTER ACTION IN HOMOGENEOUS CATALYSIS. I. COPPER SALTS AS PROMOTERS IN THE IRON SALT CATALYSIS OF HYDROGEN PEROXIDE

1923 ◽  
Vol 45 (11) ◽  
pp. 2512-2522 ◽  
Author(s):  
Van L. Bohnson ◽  
A. C. Robertson
Keyword(s):  
Hydrogen Peroxide ◽  
Homogeneous Catalysis ◽  
Iron Salt ◽  
Copper Salts

Experimental and Modelling Approach for the Comparison of Fenton and Electro-Fenton Processes. Preliminary Results

2006 ◽  
Vol 9 (1) ◽  
Author(s):  
Truong Giang Le ◽  
Alain Bermond
Keyword(s):  
Hydrogen Peroxide ◽  
Oxygen Reduction ◽  
Organic Compounds ◽  
Fenton Reaction ◽  
Experimental Approach ◽  
Fenton Process ◽  
Iron Salt ◽  
Preliminary Results ◽  
Modelling Approach

AbstractThe Electro-Fenton is one of the processes based on the Fenton reaction, which have been investigated to improve the efficiency of classical Fenton treatment. The Electro-Fenton has been shown to be efficient in the degradation of many organic compounds. However, generally there is no true estimation of its efficiency compared to that of the classical Fenton process. This study aimed to compare the two processes using an experimental approach and modelling. First of all, degradation of hydrogen peroxide (externally applied) was studied. It was shown that the Electro-Fenton process needs smaller quantities of iron (5 times less) than the Fenton to decompose the same quantity of hydrogen peroxide. The Electro-Fenton process may also produce hydrogen peroxide in situ (oxygen reduction). This leads to an important reduction in the consumption of chemicals (hydrogen peroxide, small quantities of iron salt). Finally, a study of the degradation of phenol, when hydrogen peroxide was electrogenerated has shown the greater efficiency of Electro-Fenton compared to the Fenton process.

scholarly journals THE OXIDATION OF SODIUM LACTATE BY HYDROGEN PEROXIDE

1924 ◽  
Vol 6 (5) ◽  
pp. 509-523 ◽  
Author(s):  
George B. Ray
Keyword(s):  
Hydrogen Peroxide ◽  
Methylene Blue ◽  
Previous Treatment ◽  
Sodium Lactate ◽  
Iron Salt ◽  
Iron Solution

By means of a modification of the technique of the Osterhout apparatus it is possible to follow the production of CO2 from sodium lactate when acted upon by H2O2. The results of this process indicate that the reaction is not a simple one but is of an autocatalytic type. This conclusion is borne out by the fact that the determinations of H2O2 during the reaction show an increased amount of peroxide during the earlier stages of the reaction. This is considered to be due to the formation of a peroxide by the oxidation of the acetaldehyde (formed by the interaction of H2O2 and sodium lactate) with the oxygen of the air. When the reaction is carried out in an atmosphere of nitrogen no increase is observed. Further experiments in nitrogen tend to show that acetaldehyde is the end-product of the action of H2O2 alone. The effect of FeCl3 upon the reaction depends upon the previous treatment of the iron salt. If the iron solution is added to the H2O2 before mixing with the lactate there is an increased amount of CO2. If, however, the iron is added to the lactate before the addition of the peroxide, the action tends to inhibit the production of CO2. The reaction of H2O2 with sodium lactate is comparable to the action of killed yeast and methylene blue as determined by Palladin and his coworkers.

THE PROBLEM OF PLASTEIN FORMATION: I. THE FORMATION OF A PLASTEIN BY PAPAIN

1940 ◽  
Vol 18b (8) ◽  
pp. 255-263 ◽  
Author(s):  
H. B. Collier
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrogen Sulphide ◽  
Substrate Concentration ◽  
Enzyme Concentration ◽  
Square Root ◽  
Copper Salts ◽  
Egg Albumin ◽  
Oxidation Reduction ◽  
Optimum Ph ◽  
Hydrolysis Of

Papain, activated by cyanide, cysteine, or hydrogen sulphide, produces a plastein, a protein-like substance, from concentrated peptic or papain digests of egg albumin. This activity is suppressed by boiling, aeration, the addition of copper salts, hydrogen peroxide, iodoacetate, or alloxan, indicating that free SH groups are essential. The optimum pH for plastein formation is 4.8; that for hydrolysis of the plastein by papain is about pH 4.2. It is concluded that concentration alone controls the direction of the enzyme action, the optimum pH and oxidation-reduction conditions being practically identical for both formation and hydrolysis of plastein.The rate of plastein formation varies with substrate concentration, above a minimum value. With constant substrate concentration, the rate of plastein formation varies as the square-root of the enzyme concentration. Hydroxylamine reduces the activity of the papain by about one-half. A similar effect is produced by treatment with phenylhydrazine, followed by benzaldehyde. Phenylhydrazine alone has no effect, whereas benzaldehyde alone depresses the activity very strongly.

Peroxidase Localization in Hartmanella Trophozoites

1971 ◽  
Vol 29 ◽  
pp. 346-347 ◽  
Author(s):  
George E. Childs ◽  
Joseph H. Miller
Keyword(s):  
Hydrogen Peroxide ◽  
Ultrastructural Localization ◽  
Pathogenic Strain ◽  
Oxidative Enzymes ◽  
Differential Centrifugation ◽  
Electron Microscopic ◽  
Microscopic Studies ◽  
The Subject ◽  
Axenic Cultures

Biochemical and differential centrifugation studies have demonstrated that the oxidative enzymes of Acanthamoeba sp. are localized in mitochondria and peroxisomes (microbodies). Although hartmanellid amoebae have been the subject of several electron microscopic studies, peroxisomes have not been described from these organisms or other protozoa. Cytochemical tests employing diaminobenzidine-tetra HCl (DAB) and hydrogen peroxide were used for the ultrastructural localization of peroxidases of trophozoites of Hartmanella sp. (A-l, Culbertson), a pathogenic strain grown in axenic cultures of trypticase soy broth.

Fluorescent proteins for in vivo imaging, where's the biliverdin?

2020 ◽  
Vol 48 (6) ◽  
pp. 2657-2667
Author(s):  
Felipe Montecinos-Franjola ◽  
John Y. Lin ◽  
Erik A. Rodriguez
Keyword(s):  
Hydrogen Peroxide ◽  
In Vivo Imaging ◽  
Near Infrared ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Fluorescent Imaging ◽  
Infrared Light ◽  
Red Fluorescent Protein ◽  
Color Palette

Noninvasive fluorescent imaging requires far-red and near-infrared fluorescent proteins for deeper imaging. Near-infrared light penetrates biological tissue with blood vessels due to low absorbance, scattering, and reflection of light and has a greater signal-to-noise due to less autofluorescence. Far-red and near-infrared fluorescent proteins absorb light >600 nm to expand the color palette for imaging multiple biosensors and noninvasive in vivo imaging. The ideal fluorescent proteins are bright, photobleach minimally, express well in the desired cells, do not oligomerize, and generate or incorporate exogenous fluorophores efficiently. Coral-derived red fluorescent proteins require oxygen for fluorophore formation and release two hydrogen peroxide molecules. New fluorescent proteins based on phytochrome and phycobiliproteins use biliverdin IXα as fluorophores, do not require oxygen for maturation to image anaerobic organisms and tumor core, and do not generate hydrogen peroxide. The small Ultra-Red Fluorescent Protein (smURFP) was evolved from a cyanobacterial phycobiliprotein to covalently attach biliverdin as an exogenous fluorophore. The small Ultra-Red Fluorescent Protein is biophysically as bright as the enhanced green fluorescent protein, is exceptionally photostable, used for biosensor development, and visible in living mice. Novel applications of smURFP include in vitro protein diagnostics with attomolar (10−18 M) sensitivity, encapsulation in viral particles, and fluorescent protein nanoparticles. However, the availability of biliverdin limits the fluorescence of biliverdin-attaching fluorescent proteins; hence, extra biliverdin is needed to enhance brightness. New methods for improved biliverdin bioavailability are necessary to develop improved bright far-red and near-infrared fluorescent proteins for noninvasive imaging in vivo.

Protective effect of chitooligosaccharides on hydrogen peroxide-induced PC-12 cells death by inhibition of oxidative damage

2010 ◽  
Vol 34 (8) ◽  
pp. S27-S27
Author(s):  
Xueling Dai ◽  
Ping Chang ◽  
Ke Xu ◽  
Changjun Lin ◽  
Hanchang Huang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Oxidative Damage ◽  
Protective Effect ◽  
Pc 12 Cells ◽  
Cells Death
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