Buffer Composition effect

TABLE 4.4 Effect of Buffer Composition on Mass Recovery of Proteins from TSK-GEL G3000SW< ... 

Manipulation of buffer pH or use of additives can easily vary separation selectivity. In contrast to gel electrophoresis, a single capillary can be used to evaluate the effect of buffer composition or pH on resolution. In CZE the capillary is simply filled with a fresh electrolyte of the chosen composition between analyses. 

Dunn SD. 1986. Effects of the modification of transfer buffer composition and the renaturation of proteins in gels on the recognition of proteins on Western blots by monoclonal antibodies. Anal Biochem 157 144-153. 

Effects of buffer composition on electroosmotic flow in capillary electrophoresis. /. Microcol. Sep. 2, 176-180. 

Robustness Evaluate effects of deliberate perturbations of system (e.g., pH, sample stability, temperature, buffer composition, etc.)... 

Fig. 10.1 Effect of buffer composition on the ESI-FTICR-MS spectrum of myoglobin. The spectrum in (a) was acquired from a solution containing 2 pM myoglobin in 50% MeOH, 49% H2O, and 1% HOAc. Peaks corresponding to apomyoglobin and free heme dominate the spectrum. The spectrum in (b) was acquired from a solution...

Spremulli, G. H. 1942. A study of the effects of time, buffer, composition, specifications, and ionic strength on the surface tension of solutions of /3-lactoglobulin. Pub. 510. University of Michigan Microfilms, Ann Arbor, Michigan, p. 130. 

Robson, H., Craig, D.Q.M., and Deutsch, D. (2000) An investigation into the release of cefuroxime axetil from taste-masked stearic acid microspheres. II. The effects of buffer composition on drug rtelteafee. 

Gomez G, Pikal MJ, Rodriguez-Homedo N. Effect of initial buffer composition on pH changes during far-from-equilibrium freezing of sodium phosphate buffer solutions. Pharm Res 2001 18 90-97. 

The preceding approach, in principle, also enables the effect of the valency and the activity coefficients of different displacer salts to be considered in the evaluation of the Zc or the corresponding z values for any HP-IEX system. For example, if the retention results for a series of polypeptides and/or proteins chromatographed with the same HP-IEX sorbent, column, flow rate, elution conditions, buffer composition, pH, and at the same temperature, but with NaCl or CaCl2 as the displacing salt are compared, then the relative differences between these two salt systems can be evaluated in terms of a free energy selectivity parameter r such that... 

TABLE 5 Effect of Buffer Composition on the Elution Volume of IgG Fraction from CM HyperD F... 

As with any assay, conditions for a QES assay must be optimized in terms of buffer composition, particularly pH and potential salt and metal ion effects. Eurther-more, the specificity of cleavage should be verified by an independent method, such as reverse-phase HPLC. Given the aromatic nature of both fluorophore and quencher, even low levels of QFS and cleavage products can be easily detected by UV absorbance. This method will also determine whether any absence of fluorescence is due to lack of cleavage or to a low fluorescent yield, as occurred with some of the ECE substrates discussed in Note 1. 

Eq. (18) allows one to calculate the protein solubility in a wide range of cosolvent concentrations if information regarding (i) the composition dependence of the preferential binding parameter and (ii) the properties of the protein-free mixed solvent such as the molar volume and the activity coefficients of the components are available. In addition, one should mention that Eq. (18) was obtained for ternary mixtures (water (l)-protein (2)-cosolvent (3)). However, those mixtures contain also a buffer, the effect of which is taken into account only indirectly through the preferential binding parameter. Another limitation of Eq. (18) is the infinite dilution approximation, which means that the protein solubility is supposed to be small enough to satisfy the infinite dilution approximation (y2 = where is the activity coefficient of a protein at infinite dilution). 

Table 3. Example of the comparative effect of buffer composition on solubility and activity in receptor binding vs. cell-based assays.

Effects of pH, buffer composition and temperature on reaction rates of enzymes... 

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