Methylene blue binding

It has been shown that methylene blue binds to DNA in a manner similar to that of acridine orange, with the intercalated solute being coplanar with the base pairs at low dye/polymer ratios and low ionic strengths [89]. The induced CD data indicated the existence of two origins for the observed chirality. At low ratios of dye/polymer, the CD is... 

Rohs, R., Sklenar, H., Lavery, R. and Roder, B. (2000) Methylene blue binding to DNA with alternating GC base sequence a modeling study. J. Am. Chem. Soc. 122, 2860-2866... 

We analyzed many of these pulps by IGC to determine if there was an increase in donor or acceptor character for the pulp or if the dispersive energy characteristics of the pulp were changed in a manner that correlates to the methylene blue binding result. Table II shows the surface acid-base characteristics and dispersive component for these pulps. The ability to act as a Lewis acid was the only statistically significant correlation when compared with methylene blue binding, with rs = -0.56 (Spearman rank-order correlation coefficient) and P = 0.03. The ability to act as a Lewis base, the dispersive component, and the ratio of acid to base had no relationship with methylene blue binding. 

Because methylene blue is a cationic dye, it would be expected to have activity as a Lewis acid. The correlation with methylene blue was weak but showed the expected trend, with increased methylene blue binding being negatively correlated to increased Phloroglucinol and isovanillic acid were the only laccase substrates that increased the ATp of the fiber. All substrates other than resorcinol, 4-hydroxyphenylacetic acid, 1,2,3-trihydroxybenzene, and 1,2,4-... 

Methylene blue binding does not predict the Lewis acid-base characteristics of the pulp but might be useful as an indicator of other properties in a product derived from the pulp. It does indicate that some change was made in the binding properties of the pulp. 

The aqueous solution of methylene blue is not decolorised by sodium hydroxide the blue water-solubie ammonium base is formed. The dye is converted by reducing agents into the easily oxidisable leuco-base. The following experiment, which demonstrates the formation of methylene blue by the introduction of sulphur between the rings of Bind-schedler s green, is very instructive. 

Okuda, T., Mori, K., and Hatano, T., Relationships of the structures of tannins to the binding activities with hemoglobin and methylene blue. Chem. Pharm. Bull. 33, 1424, 1985. 

The enzyme was found to be unstable in soluble form and to bind FAD tightly with a K of 61 pM. Its selectivity for an acceptor of electrons was demonstrated by its failure to reduce ferricyanide, dichlorophenolindophenol, methylene blue, or cytochrome c (directly). Tantalizingly the loss of activity was nearly immediate in the presence of ATP, prompting the suggestion that ATP may be a physiological regulator of the activity of the enzyme. Activity was stimulated by dithiothreitol at low concentrations and loss of activity was stimulated by salts and EDTA. 

Photooxidation of alkaline phosphatase in the presence of methylene blue and Rose Bengal causes loss of activity for both native and apo-enzyme. In the case of the native enzyme, zinc protects 2 to 3 of the 16 histidine residues. The rate of oxidation of tryptophan is not affected by zinc, and there was no loss of tyrosine. Also, photooxidation of the apoenzyme diminishes zinc binding. It would appear that histidine residues play a role in binding the two zinc ions necessary for enzymic activity (91). 

RNA-dye binding Methylene blue-AA6M nm Pyronine-fluorescence (406, 407) (408)... 

Carbon monoxide serves as the sole carbon and energy source for the carboxydo bacteria under aerobic conditions. Using water as the oxygen donor, carbon monoxide oxidase catalyzes the hydroxylation of carbon monoxide, giving carbon dioxide or bicarbonate for assimilation. Most work has been carried out on the enzyme from Pseudomonas carboxydovorans.,ftJ7>W38 The activity of carbon monoxide oxidase is considerably stimulated upon anaerobic treatment with sulfide and dithionite, or by aerobic treatment with selenite. The binding of selenite to the oxidase specifically activates the CO — methylene blue reaction.1039 The molybdenum cofactor liberated from selenium-activated carbon monoxide oxidase does not contain selenium. Here, then, the... 

Electrochemical indicator methods are based on the application of redox probe that undergoes oxidation and reduction transition due to electron transfer from electrode surface to a probe. In 2005, several studies that used methylene blue (MB) as an electrochemical indicator were published. MB is positively charged low-molecular-weight compound that can be reduced by two electrons to a leucomethylene blue (LB). The reduction process can be effectively monitored, e.g., by differential pulse voltammetry or coulometry. In presence of redox probe Fe(CN)6, the LB is oxidized to MB and the system is regenerated [44,45]. In papers by Hianik et al. [31,46], MB was used as the indicator of detection of interaction of human thrombin with DNA aptamer. The method of detection is schematically shown in Fig. 33.3B. MB binds both to DNA and to the protein. For charge transfer from electrode to MB, i.e., for MB reduction, it is important that MB should be close to the electrode surface. Therefore, the charge transfer from the electrode... 

Basic dyes such as methylene blue or toluidine blue are positively charged at the pH of most staining solutions used in histology. Thus the dyes bind to acidic (i.e., those that become negatively charged on dissociation of a proton) substances in the cell. These acidic molecules are therefore referred to as basophilic substances. Give some examples of basophilic substances. 

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