Glutathione promoted Fenton degradation: a cocatalyst based on the –HS/–S–S– cycle with hydroxyl radicals

2020 ◽  
Vol 6 (3) ◽  
pp. 515-522
Author(s):  
Xuwen Da ◽  
Daojian Tang ◽  
Ling Wang ◽  
Jiahai Ma
Keyword(s):  
Hydroxyl Radicals ◽  
Sulfhydryl Compounds

Sulfhydryl compounds effectively promote Fenton degradation through the establishment of the –HS/–S–S cycle with hydroxyl radicals.

scholarly journals Resting chondrocytes in culture survive without growth factors, but are sensitive to toxic oxygen metabolites.

1990 ◽  
Vol 111 (1) ◽  
pp. 257-260 ◽  
Author(s):  
T Tschan ◽  
I Höerler ◽  
Y Houze ◽  
K H Winterhalter ◽  
C Richter ◽  
...  
Keyword(s):  
Growth Factors ◽  
Hydroxyl Radicals ◽  
Resting Cells ◽  
Ferrous Ions ◽  
Toxic Compounds ◽  
Serum Free ◽  
Dense Suspension ◽  
Sulfhydryl Compounds ◽  
Low Cell Density ◽  
Oxygen Metabolites

Chondrocytes in dense suspension culture in agarose survive in serum-free DME because they secrete low molecular mass compounds supporting their own viability. This activity can be replaced by pyruvate, or sulfhydryl compounds, e.g., cysteine or dithioerythritol. Catalase, an enzyme decomposing H2O2, also protects the cells, whereas superoxide dismutase has no effect. Therefore, chondrocytes in culture are sensitive to toxic compounds derived from molecular oxygen, i.e., hydroxyl radicals or hydrogen peroxide spontaneously generated in DME containing ascorbate and ferrous ions. Poly-ADP-ribosylation is an important step in the cascade of events triggered by these compounds. To survive, chondrocytes do not require stimulation by growth factors. They remain resting cells in fully defined, serum-free culture also at low density. Proliferation and hypertrophy can be induced by serum, but not by low cell density alone.

Trihalomethane Formation Potential and Disinfection

1992 ◽  
Vol 27 (1) ◽  
pp. 185-202
Author(s):  
C.R. Erland Jansson
Keyword(s):  
Hydroxyl Radicals ◽  
Giardia Lamblia ◽  
Test Results ◽  
Formation Potential ◽  
Trihalomethane Formation Potential ◽  
Resistant Species ◽  
Low Levels ◽  
High Concentrations ◽  
Operational Data ◽  
Surface Water Supply

Abstract The UVOX process was developed to reduce the high concentrations of trihalomethanes, a potentially hazardous disinfection by-product found in a surface water supply for a community in northeastern Saskatchewan. Pilot plant tests were conducted at a throughput of 1.25 l/s utilizing UV to produce hydroxyl radicals from photolysis of H2O2 with air cooled UV units. These tests continued through 1985 andl986 to provide operational data for all seasons of the year. Test results indicated that the UVOX process was effective in reducing trihalomethane formation potential to very low levels. Recent concerns have also centred on the biocidal effectivenesss of disinfectants, particularly when applied to inactivation of resistant species of microogranisms, such as the cysts of Giardia lamblia. The UVOX process in a single pass configuration slightly enhanced the ability of UV to inactivate Giardia cysts.

Enhancement of hydroxyl radical generation by phenols and their reaction intermediates during ozonation

1998 ◽  
Vol 38 (6) ◽  
pp. 147-154 ◽  
Author(s):  
Hideo Utsumi ◽  
Sang-Kuk Han ◽  
Kazuhiro Ichikawa
Keyword(s):  
Hydroxyl Radical ◽  
Hydroxyl Radicals ◽  
Spin Trapping ◽  
Active Species ◽  
Generation Rate ◽  
Peak Height Ratio ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Phenol Derivatives ◽  
Semiquinone Radicals

Generation of hydroxyl radicals, one of the major active species in ozonation of water was directly observed with a spin-trapping/electron spin resonance (ESR) technique using 5,5-dimethyl-1-pyrrolineN-oxide (DMPO) as a spin-trapping reagent. Hydroxyl radical were trapped with DMPO as a stable radical, DMPO-OH. Eighty μM of ozone produced 1.08 X 10-6M of DMPO-OH, indicating that 1.4% of •OH is trapped with DMPO. Generation rate of DMPO-OH was determined by ESR/stopped-flow measurement. Phenol derivatives increased the amount and generation rate of DMPO-OH, indicating that phenol derivatives enhance •OH generation during ozonation of water. Ozonation of 2,3-, 2,5-, 2,6-dichlorophenol gave an ESR spectra of triplet lines whose peak height ratio were 1:2:1. ESR parameters of the triplet lines agreed with those of the corresponding dichloro-psemiquinone radical. Ozonation of 2,4,5- and 2,4,6-trichlorophenol gave the same spectra as those of 2,5- and 2,6-dichlorophenol, respectively, indicating that a chlorine group in p-position is substituted with a hydroxy group during ozonation. Amounts of the radical increased in an ozone-concentration dependent manner and were inhibited by addition of hydroxyl radical scavengers. These results suggest that p-semiquinone radicals are generated from the chlorophenols by hydroxyl radicals during ozonation. The p-semiquinone radicals were at least partly responsible for enhancements of DMPO-OH generation.

Total lactate dehydrogenase and its isoenzymes in serum in the presence of penicillamine and other sulfhydryl compounds.

1977 ◽  
Vol 23 (2) ◽  
pp. 229-233 ◽  
Author(s):  
L L Gershbein ◽  
K G Raikoff
Keyword(s):  
Lactate Dehydrogenase ◽  
Disc Electrophoresis ◽  
The Other ◽  
Rat Serum ◽  
Initial Concentration ◽  
Ldh Isoenzymes ◽  
Allosteric Effectors ◽  
Sulfhydryl Compounds

Abstract Toward delineation of changes in total lactate dehydrogenase (LDH) and in the distribution of LDH isoenzymes as assessed by polyacrylamide disc electrophoresis, we inbucated human and rat sera with various agents, notably sulfhydryl compounds. Although artefacts were apparent when these agents were used without preliminary adjustment of pH, we saw little alteration in total unitage when one or two volumes of serum was mixed with one volume of any of several thiols, especially penicillamine, at an initial concentration of 0.4 mol/liter and pH 7.0-7.5. Under these conditions, penicillamine caused a loss in LDH-5 after incubation for 1 h at 25 degrees C together with small decreases in mobility of the other four isoenzymes toward the anode. A zymosan region appeared below the albumin and tracking dye area. With longer periods of incubation of rat serum with penicillamine or alpha-mercaptosuccinate, a novel band in the zymogram was noted just above the LDH-4 peak. The observations are discussed in terms of allosteric effectors.

The aqueous photochemistry of sodium 9,10-anthraquinone-2-sulfonate

1976 ◽  
Vol 54 (4) ◽  
pp. 512-515 ◽  
Author(s):  
James Leslie Charlton ◽  
Rhonda Gail Smerchanski ◽  
Charles Eugene Burchill
Keyword(s):  
Hydroxyl Radicals ◽  
Free Hydroxyl

The aqueous photochemistry of sodium 9,10-anthraquinone-2-sulfonate is described and a new mechanism for the photohydroxylation is proposed. The participation of kinetically free hydroxyl radicals is ruled out.

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