Buffer TRIS

Since DNA degrading by BLM has been shown to be sensitive to the nature and concentration of the buffer ions which are present in solution ( ), we examined the effects of various buffers of the esr spectra and the electrochemical properties of the Fe(III) complexes. Electrochemistry allows a clear view of how one of the metal ligating sites of BLM, the 4-amino pyrimidine moiety, behaves in the presence of buffer ions. If Fe(III)BLM is synthesized from the free drug and Fe(III)(CJlO,j)3 in the absence of buffers, electrochemistry shows that the 4-amino pyrimidine remains bound to the metal ion within the pH range 4-9 where esr shows that low 

ACS Symposium Series American Chemical Society Washington, DC, 1980. 

In an effort to more clearly understand the mechanism by which bleomycin degrades DNA, three new bleomycin analogues were synthesized, 2-4. All three analogues were formed by the condensation of the primary amine function of BLM-A2 with either benzoyl chloride (2) or a sulfonyl chloride (3,4) using Schotten-Baumann conditions (l ). The compounds were purified via chromatographic means were characterized using H and nmr and po-tentiometric titration methods. Particularly noteworthy in the titration curves of the derivatives is the absence of inflections at pH values of 2.9 and 7.4. For BLM-Az, inflections at these pH values correspond to the loss of a proton from the protonated, but hydrogen bonded, secondary amine function (Eq. 1) and a loss of a proton from the protonated primary amine function respectively (Eq. 2). 

In contrast to BLM-A2, neither of the new derivatives facilitated the oxidation of Fe(II) to Fe(III) in the atmosphere (10). Esr studies of aqueous solutions containing equimolar amounts Fe(II)(C 0i,)2 and the analogues, 2-4 at pH, 7.0 showed the lack of formation of Fe(III). Similar observations have been reported for 

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Fig. 5. Anion-exchange separation of insulin and insulin A- and B-chains, over diethylaminoethyl (DEAF) in a 10.9 x 200 mm column having a volume of 18.7 mL. Sample volume is 0.5 mL and protein concentration ia 16.7 mAf Tris buffer at pH 7.3 is 1 mg/mL for each component ia the presence of EDTA. Eluent (also 16.7 mAf Tris buffer, pH 7.3) flow rate is 1.27 ml,/min, and protein detection is by uv absorbance at 280 nm. The straight line depicts the salt...

Dibydropteridine reductase (from sbeep liver) [9074-11-7] Mr 52,000 [EC 1.6.99.7]. Purified by fractionation with ammonium sulfate, dialysed versus tris buffer, adsorbed and eluted from hydroxylapatite gel. Then run through a DEAE-cellulose column and also subjected to Sephadex G-lOO filtration. [Craine et al. J Biol Chem 247 6082 1972.]... 

FIGURE 9.22 Analysis of poly(vinyl pyrrolidone). Eluent 0.1 M Tris buffer, pH 7. Flow rate I ml/ min. Columns PSS Suprema 10 /itm, 100 + 1000, 8 x 300 mm. Oven temp 30°C. Detection Rl. Standards PSS polyvinylpyridin standards. 

The 4-hydroxyphenacyl group is removed by photolysis (300 nm, CH3CN, tris buffer). ... 

DEAE-cellulose chromatography. The 50% ethanol solution is poured onto a column of DEAE cellulose (2.6 x 10 cm), and F adsorbed at the top is eluted with 20 mM Tris buffer, pH 7.5, containing 0.2 M NaCl. A low pressure of argon gas is applied to accelerate the flow rate. The fractions containing F are combined, concentrated, and desalted using ethanol. 

Fig. 7.1.3 Influence of the buffer and the type of peroxide on the luminescence reaction of Chaetopterus photoprotein. The reaction was initiated at zero time by the addition of a peroxide (old dioxane or H2O2) and FeSC>4 in each case, with successive additions of FeSC>4 or H2O2 at the time indicated with an arrow. In the experiments of the two upper curves, 10 pi of old dioxane and 1 pi of lOmM FeSC>4 were added at zero time, followed by 1 pi of 10 mM FeSC>4 at each arrow. In the experiments of the two lower curves, 50 pi of 10 mM H2O2 and 20 pi of 10 mM FeSC>4 were added at zero time, followed by 50 pi of 10 mM H2O2 or 20 pi of 10 mM FeSC>4 at each arrow. All in 5 ml of 10 mM phosphate or Tris buffer, pH 7.2. From Shimomura and Johnson, 1966.

Fig. 9.9 Luminescence spectrum of a young fruiting body of Fanellus stipticus (1) the chemiluminescence spectra of PM-1 in the presence of CTAB (2) hexadecanoyl-choline iodide (3) and tetradecanoylcholine chloride (4). Chemiluminescence was elicited with Fe2+ and H2O2 in 50mM Tris buffer, pH 8.0, containing 0.18mM EDTA.

Activation of the M. citricolor luciferin precursor with decylamine. The following mixture was incubated overnight at room temperature (23 24°C) luciferin precursors before the separation of isomers by F1PLC (50 pi, activity 2 x 1012 photons by the assay method described above), 30 mM Bis-tris buffer (pH 6.4, 4.5 ml) acetonitrile... 

Assay of Luminodesmus photoprotein. A sample solution (10 100pl) is mixed with 2ml of 10 mM Tris buffer, pH 8.5, containing 0.1 mM ATP and 1 mM MgCl2, and the peak intensity of the luminescence is measured. After mixing, the light intensity reaches its maximum in a few seconds, then gradually diminishes in... 

Assay of luminescence activity. Luciferin solution (1 ml) is mixed with 1.2 ml of 0.5 M Tris buffer (pH 8.2) and 0.3 ml of luciferase solution. The luminescence reaction is initiated by the injection of 0.5 ml of 0.176 mM H2O2 to the luciferin-luciferase mixture. The light emission is characterized by a flash of light, followed by a rapid decay to a much lower steady-state level (Fig. 10.4.1). The maximum light intensity of the flash is taken as the measure of the luminescence activity. 

Fig. 10.4.2 The effects of temperature (left panel) and pH (right panel) on the peak intensities of the Balanoglossus luminescence reaction. In the measurements of the temperature effect, 0.5 ml of 0.176 mM H2O2 was injected into a mixture of 1.2 ml of 0.5 M Tris buffer (pH 8.2), 0.3 ml of luciferase, and 1 ml of luciferin, at various temperatures. For the pH effect, the Tris buffer (pH 8.2) was replaced with the Tris buffers and phosphate buffers that have various pH values, and the measurements were made at room temperature. From Dure and Cormier, 1963, with permission from the American Society for Biochemistry and Molecular Biology.

The open channel has in most cases a selective permeability, allowing a restricted class of ions to flow,for example Na+, K+, Ca++ or Cl- and, accordingly, these channels are called Na+-channels, K+-channels, Ca -channels and Cr-channels. In contrast, cation-permeable channels with little selectivity reject all anions but discriminate little among small cations. Little is known about the structures and functions of these non-selective cation channels [1], and so far only one of them, the nicotinic acetylcholine receptor (nAChR, see Nicotinic Receptors), has been characterized in depth [2, 3]. The nAChR is a ligand-gated channel (see below) that does not select well among cations the channel is even permeable to choline, glycine ethylester and tris buffer cations. A number of other plasma... 

Irreversible reaction of [18] iodine with acetylsalicylic acid, aethaverine, amidopyrine, ascorbic acid, benzo-caine, quinine, dihydrocodeine, fluorescein, glycine, hydrocortisone acetate, isoni-azid, metamizole, papaverine, paracetamol, phenacetin, phenol-phthalein, piperazine, resorcinol, salicylic acid, salicylamide, sulfaguanidine, thymol, triethanolamine, tris buffer detection by reaction chromatography... 

The GMT in human serum reacts most rapidly with Y-glutamyl-p-nitroanilide at pH 8.2. The same activity is found in 2-amino-2-methylpropane-l 3 diol, diethanolamine, triethanolamine and tris buffers. Magnesium ions have no effect on the activity but favor the solubilization of the substrate. Bondar and Moss (54) found that free glutamate, due to elevated serum glutamate concentrations or glutamate released by substrate breakdown, increases the apparent GMT activity. They concluded that the assay should be performed in the presence of 1.0 vM/1 glutamate in order to reduce the possibility of falsely elevated results. This was not observed by others. Rowe and co-workers have indicated that certain batches of p-nitroanilide substrate contain impurities which may reduce GMT activity and increase the values ( ). Huesby and Stromme (56) confirmed the presence of such impurities and recommended pyridine extraction for substrate purification. 

Figure 6, High pressure liquid chromatogram of creatine kinase isoenzymes. First peak, MM second peak, BB. Conditions 50 cm X 4.8 mm (i.d.) column with yydac porous layer bead anion exchange mobile phase, step gradient Solvent A, 10 mmol/liter Tris buffer, pH 8.3 solvent B, 10 mmol/liter Tris buffer, pH 7.0,0.5 mol KCl flow rate, 2 ml/min detection, collected fractions assayed (45).

The kinetics were followed by measuring the increase in absorbance at 400 nm due to the formation of the p-nitrophenoxide anion in a tris buffer solution at pH 8.5. The substrate was used in excess over the free base catalyst, whose concentration was calculated from spectrophotometric data. 

Cd2+ 100-1000 pM Alcaligenes spp. and Pseudomonas spp. Tris-buffered minimal medium 84... 

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