EDTA fraction

Among the complexing agents that find use as titrating agents, ethylenediamine-A,A(A, A-tet-raacetic acid (acronym EDTA, and equation abbreviation, H4Y) is by far the more important, and it is used in the vast majority of complexometric titrations. The successive acid values of H4Y are pKi = 2.0, pisTj = 2.67, = 6.16, pTCt = 10.26 at 20°C and an ionic strength of 0.1. The fraction... 

To correct the formation constant for EDTA s acid-base properties, we must account for the fraction, ayi-, of EDTA present as Y . 

Sodium alginate [9005-38-3]. Freed from heavy metal impurities by treatment with ion-exchange resins (Na -form), or with a dilute solution of the sodium salt of EDTA. Also dissolved in 0. IM NaCl, centrifuged and fractionally ppted by gradual addition of EtOH or 4M NaCl. The resulting gels were centrifuged off, washed with aq EtOH or acetone, and dried under vacuum. [Buchner, Cooper and Wassermann J Chem Soc 3974 7967.]... 

The eluted luciferase is precipitated with ammonium sulfate. The precipitate is dissolved in 1 mM Tris-HCl, pH 8, containing 0.1 mM EDTA, 3 mM DTT and 0.1 M NaCl, and chromatographed on a column of Sephacryl S-300 (2.6 x 97 cm) using the same buffer. Luciferase is eluted in two peaks, corresponding to the molecular weights of about 420,000 (an aggregate) and 130,000, in a ratio of about 8 1. The fractions of these two peaks are pooled separately the Mr 420,000 luciferase is concentrated by either ultrafiltration or precipitation with ammonium sulfate. 

An affinity sorbent based on WPA-PG carrying immobilized human IgG was applied to the isolation of the first component of the complement (Cl) from human serum and for its separation into subcomponents Clr, Cls and Clq by the one-step procedure [126,127]. Cl was quantitatively bound to the sorbent at 0 °C. The activities of subcomponents Clq and Clr2r2 in the unbound part of the serum were found to be 0.8% and 3.3% of the initial activities in serum. This fraction, therefore, could be used as a R1 reagent for determining the hemolytic activity of Cl. Apparently, the neighboring macromolecules of immobilized IgG resemble to some extent an immune complex, whereas Cl formation is facilitated due to the mobility of polymer chains with the attached IgG macromolecules (Cl is usually dissociated in serum by 30%). After activation of bound Cl by heating (30 °C, 40 min) the activated subcomponent Clr is eluted from the sorbent. Stepwise elution with 0.05 mol/1 EDTA at pH 7.4 or with 0.05 mol/1 EDTA + 1 mol/1 NaCl at pH 8.5 results in a selective and quantitative elution of the activated subcomponent Cls and subcomponent Clq. 

The SI70 supernatant (220 ml) was made to 40 % saturation with solid ammonium sulfate, stirred for 20 min, and then the precipitate was collected by centrifugation at 15,000 g for 15 min. The precipitate was suspended in small volume of buffer B-50 at pH 7.6 containing 20 mM HEPES/KOH, 0.1 mM EDTA, 1 mM dithiothreitol, 10 % (v/v) glycerol, and 50 mM potassium acetate. The 60 % saturated ammonium sulfate solution was prepared similarly. Protein concentrations for 0 - 40 % and 40 - 60 % ammonium sulfate fractions were 4.2 mg/ml and 4.7 mg/ml, respectively. 

The oxidation of ethylenediaminetetraacetic acid (EDTA) by Pu02 and Np02 to give the quinquevalent metal ions in perchlorate media is first-order in both oxidant and substrate and the stoichiometry, d[M(VI)]/ A [EDTA], is 6 in both cases. The Np(VI) oxidation shows a fractional dependence on acidity and has parameters E = 23.0 kcal.mole , AS — 12.3 eu. 

Figure 3 Size fractionation of EDTA-soluble polyuronides from Rutgers and transgenic fruit juice processed by cold- and hot-break methods. Pectin from processed juice was extracted as ethanol-insoluble solids and size fractionated on a Sepharose CL4B column. Under the same chromatographic conditions, elution of the branched dextrans with average molecular mass 2000, 500, 252, 151, 40 and 17.7 kD-peaked in fraction number 46, 50, 54, 62, 67 and 72, respectively. Modified from Thakur et al. [23].

The molecular weight distribution of cell wall polysaccharides was estimated by gel filtration with a TOSOH TSK gel G4000 PWXL (7.8 x 300 mm) column equilibrated and eluted with 0.05 M sodium acetate, 0.01 M EDTA, 0.05 M NaCl (pH 5.0) in polyuronide and 0.05 M sodium citrate, 0.1 M NaCl (pH 5.5) in the hemicellulose fraction. Samples (1 mg/ml) of 100 ml were injected. The eluate was monitored by a refractive index detector (Shimadzu R1D-6A, Kyoto, Japan) and collected at the fraction size of 0.4 ml. 

Quevauviller Ph, Herzig R. and Muntau H (1996b) Certified reference material of lichen (CRM 482) for the quality control of trace element biomonitoring. Sci Total Environ 187 143-152 Quevauviller Ph, Lachica M., Barahona E, Rauret G, Ure A, Gomez A, and Muntau H (1997) The certification of the EDTA-extractable contents (mass fractions) of Cd, Cr, Ni, Pb, and Zn and of the DTPA-extractable contents (mass fractions) of Cd and Ni in calcareous soil by the extraction procedures given CRM 600. EUR Report 17555 Quevauviller Ph. Maier EA, and Griepink B, eds. (1995) Quality Assurance for Environmental Analysis. Elsevier. Amsterdam. 

Example polysome profiles from sucrose gradient fractionation of HeLa cell lysates, either untreated or treated with EDTA, are shown in Fig. 6.4A and B. The polysome profile of untreated HeLa lysates shows three defined peaks in less dense fractions (6 to 9), which correspond to the 80S, 60S, and 40S peaks (Fig. 6.4A). Treatment of lysates with 30 /iM EDTA results in ribosome dissociation leaving predominantly free 60S and 40S subunits... 

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