Of 2,6-dichlorophenol-indophenol

DPIP solution—Dissolve 67.5 mg of 2,6-dichlorophenol-indophenol (DPIP) solution in 250 ml of distilled water. 

Finally, among the organic oxidative reagents, the possibility has been reported of the application of 2,6-dichlorophenol-indophenol for the titration of ascorbic acid.d ) When the current is measured at the potential of the limiting current of ascorbic... 

Fig. 3. Example of the performance of the apparatus. The test reaction was the reduction hy ascorbate of 2,6-dichlorophenol-indophenol, measured at 600 nm. The interval between points is 0.5 ms. The figure is redrawn from the computer output to an X-Y recorder.

Standard dye solution 10 mg of 2, 6 - dichlorophenol -indophenol (DCPIP) (BDH) was dissolved in deionized water at 80 C, cooled, and its volume made upto 200 ml. Its strength was standardized by the addition of either deionized water or more concentrated dye solution until 5 ml of the dye solution when mixed with 2 ml of deionized water, gave a reading of 390 on the scale of the Klett-Summerson colorimeter or an optical density (O.D.) of 0.78. This standardization of the dye solution was done every time Just prior to starting of estimations. 

Measurement of photosynthetic electron transport reactions Photosynthetic electron transport reactions were measured with an oxygen electrode of Rank Brothers (England). The conditions are summarized in Table 1. In order to determine optimal conditions the reduction of 2.6 dichlorophenol indophenol was measured in dependance on its pH and the KCl-conceniration. These experiments show that the maximal reaction was obtained in 30 mM tricine buffer at pH 6.5 and a KCl addition of 20 mM. 

After prolonged EDTA and lysozyme treatment, Anacystis can be converted to spheroplasts (Peschek et al.,1983). We have found that the electron transport activity of these spheroplasts is dominated by a KCN and DCMU insensitive light-induced O2 uptake, which occurs via a post-photosystem I autoxidizable endogenous intermediate. This activity is reminiscent of that reported by Honeycutt, Krogmann (1970) with cell-free cyanobacteria thylakoid fragments, except that it does not require exogenous autoxidizable acceptors like methyl viologen. The spheroplasts were also found to be capable of a dark reduction of 2,6-dichlorophenol indophenol (rate, 12 pmoles/mg Chi a h), which was enhanced (2.5x) in the presence of 1 mM KCN, and was partially inhibited by 10 mM KCl. 

To determine the depth that ozone could diffuse into the soils, reduced 2, 6-dichlorophenol-indophenol was impregnated onto sand. The sand was placed in an atmosphere containing 980 yg/m ozone for 2 hr and the depth of ozone penetration was measured as the depth that the reduced dye on the sand was oxidized. By this measure, ozone penetrated less than 20 mm into sand (Blirni and Tingey, unpublished). 

Dichlorophenol-indophenol sodium salt (2H2O) [620-45-1 ] M 326.1, e = 2.1 x 10 at 600nm and pH 8. Dissolved in O.OOIM phosphate buffer, pH 7.5 (alternatively, about 2g of the dye was dissolved in 80ml of M HCl), and extracted into ethyl ether. The extract was washed with water, extracted with aqueous 2% NaHCOj, and the sodium salt of the dye was ppted by adding NaCl (30g/100ml of NaHCOj soln), then filtered off, washed with dilute NaCl soln and dried. 

It is often possible to quantify the presence of natural molecules in biological samples without actually isolating the molecules. Two such analyses will be completed in this experiment (1) serum cholesterol will be measured by coupling its enzyme-catalyzed oxidation to the peroxidase-catalyzed formation of a chromogen, and (2) the presence of vitamin C in dietary materials will be detected and quantified by redox titration with 2,6-dichlorophenol-indophenol. 

Chlorides, alkyl 2,6-Dichlorophenol indophenol Variety of spots 1... 

The redox mediator 2,6-dichlorophenol indophenol, can mediate electron transfer from and to the redox enzyme, cytochrome c. The mediator was switched between the oxidized and reduced forms by the application of a potential using optically transparent electrodes in a thin-layer cell. From the absorbances of the oxidized and reduced form of the enzyme, the ratio of their concentrations at various potentials was obtained. Calculate the formal potential E° of the enzyme from the data given in Table E.l. Confirm that the enzyme redox process involves one electron transfer. (Contractor)... 

Since the CKX activity has been discovered more than 30 years ago, numerous inhibitors of the enzyme were reported. Synthetic derivatives of diphenylurea, e.g, 7V-(2-chloro-4-pyridyl)-iV-phenylurea and 7V-phenyl-7V-l,2,3-thidiazol-5-urea, are strong CKX inhibitors [166-168], In the presence of oxygen as the only electron acceptor, the inhibitions were described as noncompetitive and uncompetitive, respectively. However, for the maize enzyme ZmCKXI and with 2,6-dichlorophenol indophenol as the electron acceptor, the inhibition appears to be competitive towards isopentenyladenine [142] and uncompetitive towards 2,6-dichlorophenol... 

The mediator 2,6-dichlorophenol indophenol (DCPIP) has been used by Mindt et al. (1973). Mor and Guamaccia (1977) employed the [Fe(CN)e] /[Fe Nld4- couple and performed difference measurements with a GOD sensor and an auxiliary electrode to eliminate the influence of mediator-consuming side reactions. The concentration of hydro-quinone formed from benzoquinone in the GOD reaction has been measured by Geppert and Asperger (1987). 

Ascorbic Acid. The 2,6-dichlorophenol indophenol colorimetric method (11) was used to determine the ascorbic acid content of the samples. 

Complex III - Complex III contains a diversity of electron carrying proteins. They include cytochrome b, iron sulfur centers, and cytochrome cl. Cytochrome b is the first of the heme-carrying proteins (Figure 15.6) involved in electron transport. Passage of electrons from cytochrome b to the iron sulfur centers can be blocked by antimycin A. Also, the artificial electron acceptor phenazine methosulfate can accept electrons from cytochrome b and 2,6-dichlorophenol-indophenol can accept electrons from the iron sulfur proteins (Figure 15.9). The crystal structure of the redox components of complex III from bovine heart mitochondria is shown in Figure 15.16... 

Hsu et ah [6] developed an ass for the high-affinity Mn-binding site in PS II. In this assay /xM concentrations of Mn competitively inhibit 1,5-diphenylcarbazide (DPC) supported 2,6-dichlorophenol indophenol (DCIP) electron transport. Using this assay on PS II membranes modified with proteases and amino acid chemical modifiers, we have identified four components in the high-affinity Mn-binding site, corresponding to the four Mn required for functional Oj evolution. 

The rate of PS II electron transport was measured as DCPIP(2/6-dichlorophenol indophenol) reduction using a Hitachi 557 spectrophotometer as described earlier(7). PS I electron transport from the artificial electron donor was assayed as O2 uptake using a Hansatech electrode at 25 C under saturating white light from a slide projector fitted with a 150W Halogen lamp (Photophone Ltd./ India). 

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