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At least 37 records · Page 2Linked to original sources
PubMed1988

Reduction of exogenous quinones and 2,6-dichlorophenol indophenol in cytochrome b-deficient yeast mitochondria: a differential effect on center i and center o of the cytochrome b-c1 complex.

The reduction of duroquinone (DQ), 2,3-dimethoxy-5-methyl-6-decyl-1,4-benzoquinone (DB), and dichlorophenol indophenol (DCIP) by succinate and NADH was investigated in yeast mitochondria which have no spectrally detectable cytochrome b. Succinate reduces DB in the cytochrome b-deficient mitochondria at rates comparable to that observed in wild-type mitochondria, suggesting that succinate:ubiquinone oxidoreductase is unaffected by the lack of cytochrome b. In the mutant mitochondria, succinate does not reduce DQ or DCIP at significant rates; however, NADH reduces both DQ and DCIP at rates similar to that of the wild-type mitochondria in a myxothiazol, but not antimycin, sensitive reaction. The Ki for myxothiazol in this reaction is close to that for electron transfer through the cytochrome b-c1 complex. In addition, myxothiazol does not inhibit NADH:ubiquinone oxidoreductase. These results confirm our previous suggestion that the cytochrome b-c1 complex is involved in electron transfer from the primary dehydrogenases to DQ and DCIP and suggest that cytochrome b is not the binding site for myxothiazol.

2,6-Dichloroindophenol↗
PubMed1983

NADPH-dependent reduction of 2,6-dichlorophenol-indophenol by the phagocytic vesicles of pig polymorphonuclear leucocytes.

NADPH-dependent 2,6-dichlorophenol-indophenol (DCIP) reductase activity in the homogenate of phagocytosing pig polymorphonuclear leucocytes was twice that of the resting cells and the activity in the phagocytic vesicles corresponded to the activity increment due to phagocytosis. The apparent Km value of the reductase activity in the vesicles for NADPH was 30 microM, which is similar to that of the NADPH-dependent superoxide (O2-) formation. Increasing the DCIP reductase activity by increasing the DCIP concentration caused a decrease in the O2- -forming activity, the NADPH oxidation rate being constant and independent of the dye concentration. p-Chloromercuribenzoate and cetyltrimethylammonium bromide at low concentrations inhibited the O2- -forming activity of the vesicles without inhibiting the DCIP reductase. Quinacrine inhibited both O2- formation and DCIP reduction. The DCIP reductase activity could be extracted with a mixture of deoxycholate and Tween-20, which extracts the O2- -forming activity. The reductase activity in the extract was enhanced 2-fold by the addition of FAD, and its apparent Km was 0.085 microM. These results indicate that the NADPH-dependent DCIP reductase activity of the phagocytic vesicles is catalysed by a flavin-containing component of the O2- -forming system.

2,6-Dichloroindophenol↗
PubMed1979

[Activation, by various aldoses, of dichlorophenol-indophenol reduction by endogenous constituents of a preparation of glucose dehydrogenase from Pseudomonas fluorescens].

Dichlorophenol-indophenol is reduced neither by D-glucose nor by the endogenous components of a particulate purified glucose-dehydrogenase from Pseudomonas fluorescens, when these two classes of compounds acts individually. In contrast, the dye is quickly reduced by the endogenous components when the reaction occurs in the presence of glucose, without a direct participation of glucose in the reduction. In this effect D-glucose can be replaced by D-mannose, D-galactose or D-xylose, but not by D-fructose.

2,6-Dichloroindophenol↗
PubMedDate not supplied

Aids for in vitro Mycobacterium lepraemurium investigations: estimation of oxidation-reduction potentials and pO2 with 2, 6 dichlorophenol indophenol.

The partial success in cultivating a "host-dependent" microbe provided the incentive to develop methods which may aid the growth of the organism. The oxidation-reduction potential (ORP) of NC-5, an aerobic, cysteine containing medium which supports the limited in vitro growth of Mycobacterium lepraemurium, is measurable with the redox dye, 2, 6 dichlorophenol indophenol. Both cysteine and autoclaved glucose can be used to adjust to ORP. Glucose autoclaved in phosphate buffer but not in aqueous solutions reduced the dye. The dye was also reduced in glucose solutions by atmospheres containing 10% and 1%-2% pO2. With exposure to 20% pO2 the reoxidation of the dye was slow but complete. Thus, the dye in glucose solutions provides a general method for estimating pO2 above the level of anaerobiosis. Proper adjustment and monitoring of the ORP and pO2 may enhance growth.

2,6-Dichloroindophenol↗
PubMed1979

[The influence of infusions and amino-acids on the determination of ammonia by means of indophenol-reaction (author's transl)].

It will analyse and discuss the influence of fructose-, glucose-, sorbitol- and argininmalat-infusions, of ascorbit acid and vitamin-B-complex as well as of 13 different amino-acids on the determination of ammonia by means of indophenol-reaction. With this the frequent of liver-cirrhosis i.v. administer substances trouble the determination of ammonia just as little (exception: arginin-malat), how amino-acids in physiological and little pathological range.

Amino Acids↗
PubMed1984

Indophenol method for acetaminophen in serum examined.

We show that an indophenol-based colorimetric method for acetaminophen (Clin Toxicol 15: 67-73, 1979) has less than maximal sensitivity because of (a) incomplete hydrolysis, related to suboptimal acid concentration; (b) suboptimal hydrolysis time; and (c) possible deterioration of the ammonium hydroxide reagent after 2.5 months. We have modified the method by optimizing duration of hydrolysis and color development. Results by the method correlate linearly with acetaminophen concentrations to 250 mg/L (1.66 mmol/L). Moreover, the modified method is free from interference by compounds in serum from uremic patients.

Acetaminophen↗
PubMed1999

2,6-Dichloro-phenol indophenol prevents switch-over of electrons between the cyanide-sensitive and -insensitive pathway of the mitochondrial electron transport chain in the presence of inhibitors.

To evolve a simple oxygen electrode-based method to estimate alternative respiration, one needs to develop a procedure to prevent switch-over of electrons to either pathway upon inhibition by cyanide or salicylhydroxamic acid. It was hypothesized that the inclusion of appropriate electron acceptor, possessing redox potential close to one of the electron transport carriers in between ubiquinone (branch point) and cytochrome a-a3, should be able to stop switch-over of electrons to either pathway by working as an electron sink. To test the hypothesis, 2,6-dichloro-phenol indophenol (DCPIP; redox potential +0.217 V), an artificial electron acceptor having a redox potential quite similar to the site near cytochrome c1 (redox potential +0.22 V) on the cyanide-sensitive pathway, was used with isolated mitochondria and leaf discs in the absence and presence of inhibitors (potassium cyanide, antimycin A, and salicylhydroxamic acid). Polarographic data confirmed electron acceptance by DCPIP only from the inhibited (by cyanide or salicylhydroxamic acid) mitochondrial electron transport chain, hence preventing switch-over of electrons between the cyanide-sensitive and cyanide-insensitive pathway of respiration. Results with antimycin A and reduction status of DCPIP further confirmed electron acceptance by DCPIP from the mitochondrial electron transport chain. Possible implications of the results have been discussed.

2,6-Dichloroindophenol↗
PubMed1985

The role of chloride ion on the photoreactivation of the oxygen-evolving center of tris-washed, 2,6-dichlorophenol indophenol-treated grana.

Chloride ion is found to be an essential factor in photoreactivation of the oxygen-evolving center. Tris-washed, 2,6-dichlorophenol indophenol-treated grana are low in both Mn content and oxygen-evolving activity. These grana can restore high oxygen-evolving activity, however, by incorporating Mn2+ ion under weak light in the presence of chloride and calcium ions with dithiothreitol. This restoration is called photoreactivation. When chloride ion is omitted from the medium for the photoreactivation, the recovery of oxygen-evolving activity is inhibited. Other anions, such as bromide and nitrate anions, could also mediate the reactivation; but, anions of weak acids or polyvalent strong acids were not effective. Chloride ion is also required in the light-induced H+ and Mn2+ uptake of these grana, which are essential partial reactions for the reactivation. It is therefore concluded that chloride ion plays an important role in the photoreactivation.

2,6-Dichloroindophenol↗
PubMed1980

Purification of an NADH-(dichlorophenol-indophenol) oxidoreductase from Bacillus stearothermophilus.

An NADH-(dichlorophenol-indophenol) oxidoreductase was purified 104-fold and in 25% overall yield from the thermophilic bacterium Bacillus stearothermophilus, strain PH24. After solubilization in 2M-NaCl at 70 degrees C, the enzyme was purified by ion-exchange and hydroxyapatite chromatography, followed by affinity chromatography on immobilized Cibacron Blue 3GA. The purified enzyme had a mol.wt. of 43 000 and had an absorption spectrum characteristic of flavoprotein. The enzyme activity was enhanced by FMN and by CN-. The enzyme was inhibited by EDTA and by rho-chloromercuribenzoic acid.

2,6-Dichloroindophenol↗
PubMed2004

Reducing activity of colloidal platinum nanoparticles for hydrogen peroxide, 2,2-diphenyl-1-picrylhydrazyl radical and 2,6-dichlorophenol indophenol.

Shimizu and Tsuji established a method of preparing colloidal platinum nanoparticles, whose average size is 2 nm, by ethanol reduction of H(2)PtCl(6) in the absence of protective agents for the particles. Platinum nanoparticles have negative surface potential and are stably suspended from an electric repulsion between them. The platinum nanoparticles reduced hydrogen peroxide and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) below 0.1 ppm. It is necessary to use higher concentration of platinum nanoparticles for the reduction of 2,6-dichlorophenol indophenol (DCIP) than that of hydrogen peroxide and 2,2-diphenyl-1-picrylhydrazyl radical, because reoxidation of DCIPH(2) (reduced) by oxygen was not negligible under our experimental conditions. These results indicate that electrons on platinum nanoparticles produced by the method of Shimizu and Tsuji can reduce hydrogen peroxide, DPPH radical or DCIP transferring electrons.

2,6-Dichloroindophenol↗
PubMed2002

Sensitivity improvement of ammonia determination based on flow-injection indophenol spectrophotometry with manganese(II) ion as a catalyst and analysis of exhaust gas of thermal power plant.

The sensitivity improvement of a flow-injection spectrophotometric method for the determination of ammonia was examined based on an indophenol blue coloration reaction with salicylate and hypochlorite in the presence of manganese(II) as a reaction promotion catalyst. The optimal conditions for achieving higher sensitivity of ammonia determination were examined using a three-line flow system. The limit of detection corresponding to a signal-to-noise ratio (S/N) of 3 was 0.005 mg l(-1) (approximately equal to 5 ppb) of NH4+. A calibration graph was linear in the range from 5 ppb to 1,000 ppb of ammonium ion. The relative standard deviations (n = 9) for 50 ppb and 100 ppb of ammonium ion were 6.4% and 2.2%, respectively. The proposed method was applied to the determination of ammonia in the exhaust gas of a thermal power plant. Prior to the FIA determination, ammonia in the exhaust gas was absorbed into a boric acid solution; the absorption solution was then analyzed by the proposed FIA.

Journal Article↗
PubMed2005

Validation of osmotic fragility test and dichlorophenol indophenol precipitation test for screening of thalassemia and Hb E.

The strategy for screening of thalassemia and Hb E by a combination of osmotic fragility (OF) test and dichlorophenol indophenol precipitation (DCIP) test was validated with 436 unrelated Thai subjects. Hemoglobin (Hb) typing, Hb A2 quantitation, PCR and DNA sequence analysis were used as confirmatory methods for diagnosis of thalassemia and hemoglobinopathy. The sensitivity and specificity of this strategy was 100% and 79.7%, respectively. The results assessed by two medical scientists were exactly the same with 93.3% accuracy in comparison with the confirmatory methods. A combination of OF and DCIP has been shown to be a reliable, rapid, simple and sensitive strategy for screening thalassemia and Hb E in the Thai population.

2,6-Dichloroindophenol↗