Flow dialysis

Diagram of the Womack-Colowick flow dialysis apparatus Reprinted with permission of the Journal of Biological Chennistry. 

Fig. 5. Calcium uptake of sarcoplasmic reticulum vesicles supported by different substrates followed by calcium release after substrate depletion113. The time courses of calcium uptake and calcium release were measured by flow dialysis. The reaction chamber contained 0.4 mg protcin/ml, 5 mM MgCl2,...

The biocatalyst a-chymotrypsin s ability to hydrolyze 20 is inhibited in the presence of copolymer 19a loaded with 0.2 mol% of the triphenyl carbinol units. 47b Photoirradiation of 19a results in heterolytic bond cleavage and the formation of the cationic copolymer 19b. In this polymer structure, the biocatalyzed hydrolysis of 20 is activated (V = 1.0 pM min-1). The polymer-induced photostimulated activation and deactivation of a-chymotrypsin in the different membrane environments correlates with the permeability and transport properties of the substrate 20 through the different structures of the polymer membranes.1471 Flow dialysis experiments showed that the polymer states 17a, 18a, and 19a are nonpermeable to 20, and hence the biocata-lytic functions of the immobilized enzyme are blocked. The polymer structures 17b,... 

The function of the SIO2 colloid In the photosensitized electron transfer originates from selective Interactions of the components with the Interface. The electrical properties of the Interface and the binding characteristics of the positively charged sensitizer, Ru(blpy)5, have been examined by means of flow dialysis (Kass. 1.1 x 10 K l)(22). The number of binding sites on each SIO2 particle has been determined to be 65. These Ionic sites establish an Interfaclal surface potential of ca. -170 mV. 

Flow Dialysis - Dialysis tubing is boiled in 5% NaHCOj and then in deionized water. Buffer, 10 mM HEPES-KOH, 100 mM KQ, pH 7.5, is treated for the removal of contaminating calcium by Chelex chromatography (Biorad Laboratories). EDTA is removed from protein samples by passage over two Sephadex G-25 PD-10 columns. Calcium is removed from protein samples dialyzed against HEPES-KQ buffer by Chelex chromatography just prior to flow dialysis. The concentration of calcium is determined in all solutions by atomic absorption spectrophotometry. 

Flow dialysis follows the procedmes of Colowick and Womack (1969) (17) as modified by Haiech et al. (1981) (18). The dialysis cell is described by Feldman (1978) (19). A 2 ml aliquot of protein (1-2 mg/ml) is placed into an upper Teflon chamber, and both the upper and lower chamber (0.1-0.2 ml) are temperature controlled at 25°C. A peristaltic pump that perfuses the lower chamber is set at a flow rate of 1 ml/min. Non-radioactive calciiun is added in steps to yield a final calcium concentration of 0-700 pM. Data are analyzed using the Hill equation and the Adair-Klotz equation. 

Detection Permeant ions (fluorescent probes or ion electrode) carotenoid shift anilinonaphthalen-sulfonate pH meter (inside after detergent) P-NMR flow dialysis aminoacridine... 

The related fully sulfonated, self-doped polymer poly(2-methoxyaniline-5-sulfonic acid) (PMAS 9) may be prepared under normal atmospheric pressure by the oxidation of 2-methoxyaniline-5-sulfonic acid (MAS) monomer with aqueous (NH4)2S208 in the presence of ammonia or pyridine (to permit dissolution of the MAS monomer).141 The polymerization pH was therefore >3.5. Subsequent studies showed that the product consisted of two fractions a major fraction with Mw of ca. 10,000 Da whose electrical conductivity and spectroscopic and redox switching properties were consistent with a PAn emeraldine salt, as well as a nonconducting, electroinactive oligomer (Mw ca. 2,000 Da).143 144 Pure samples of each of these materials can be obtained using cross-flow dialysis.145... 

The need for prolonged dialysis inherent in equilibrium dialysis methods has been circumvented by the development of a method in which a flow-dialysis, or rate of dialysis, procedure is employed (56). This method employs a dialysis cell with an upper chamber, containing the... 

Because of the proliferation of commercial kit methods there has been little development toward automation in T3 uptake tests. One automated procedure relies on the assessment of T3 binding by the serum, the unbound T3 being removed by continuous-flow dialysis (P15). Although initial assessments were satisfactory, the results comparing favorably with a manual T3 resin uptake and a PBI procedure, a later report (M7) indicated that the automated procedure was subject to variable error caused by a large and variable proportion of radioiodine in the dialyzate. 

Another method, which is routinely used for gradient determinations is flow dialysis [48]. In this method a compartment containing the membrane preparation and the radioactively labeled solute or indicator molecules is separated from a second compartment via a dialysis membrane. The solution in the second compartment is replaced with a constant rate and the radioactivity in the outflowing solution is monitored. The radioactivity monitored reflects the concentration of the radioactive probe in the external medium in the first compartment. Recently, an automatization of this technique has been described which considerably increases the... 

More recently, another multicommutated flow method was developed for the simultaneous determination of tartaric acid and potassium as a tool for evaluating the tartrate stability of wines (Oliveira et al., 2010). This system also resorted to inline dialysis of the samples in order to minimize matrix interferences for tartaric acid determination. A detailed study with different configurations of the dialysis unit was presented and various membrane materials were compared. The continuous-flow dialysis process was optimized for acceptor and donor channel flow rates, flow directions, and stop flow periods. 

Spohr R, Reber N, Wolf A et al. Thermal control of drug release by a responsive ion track membrane observed by radio tracer flow dialysis. J Controlled Release 1998 50 1-11. 

FIGURE 1. Comparison of the ApH in Rps. sphaeroides as measured with automated flow-dialysis and P-NMR. In the flow dialysis experiments light saturation was ascertained through a series of experiments at various light intensities and cell densities. In the flow-dialysis experiments ( C)-benzoic acid (30 yM) was used as ApH probe. 

Open symbols P-NMR closed symbols automated flow dialysis squares medium glycyl-glycine (20 mM), 20 mM N-2-hydroxy ethylpiperazine-N-2-ethane sulphonic acid, 20 mM 2-(N-morpholino)-ethane sulphonic acid,... 

Nicolay K, Lolkema JS, Hellingwerf KJ, Kaptein R and Konings WN (1981) Quantitative agreement between the values of the light induced ApH in Rhodopseudomonas sphaeroides measured with flow-dialysis and P NMR,... 

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