Compressibility studies of three proteins in CsCl solutions in the analytical ultracentrifuge

Sharp, Dan S.; Fujita, Norman; Kinzie, Kathleen; Ifft, James B.

doi:10.1002/bip.1979.360180421

Cited by 3 publications

(4 citation statements)

References 6 publications

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“…Similarly, PEDERSEN et al (18) in the following article in this journal have observed an increase in the hydration of the ~charge-ion complexes,, of ovalbumin as a function of water activity. However, the analysis by SHARP et al (25) of the data of BULL and BREESE (2) indicates no change in the hydration of egg albumin with av…”

Section: Hydrations and Water Activitiesmentioning

confidence: 99%

Buoyant and potentiometric titrations of synthetic polypeptides III. Poly-l-lysine and poly-l-histidine in five salt solutions

Ifft

Pedersen

Fujita

et al. 1978

Carlsberg Res. Commun.

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The buoyant titrations of poly-L-lysine and poly-L-histidine in CsCI, RbCI, CsBr, RbBr and KBr were measured. Large differences in buoyant densities measured at low pH were observed for both polymers. Densities in the alkali chloride solutions are lower than for the bromides and the buoyant density increases as the size of the cation decreases in the halide series. All buoyant densities converge to a common value for each polymer at high pH. These data are interpreted in terms of salt-pair formation at low pH and preferential hydrations were computed both for this charged species at low pH and for the neutral polymers at high pH. The resulting data were correlated with the water activity in each buoyant solution. The variation of hydration with water activity for the charged species is found to be similar to that previously reported for bovine serum mercaptalbumin while the hydrations of the neutral polymers are found to be nearly independent of water activity. Approximate observed ionization constants were determined for each polymer in four salt solutions.

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Section: Hydrations and Water Activitiesmentioning

confidence: 99%

Buoyant and potentiometric titrations of synthetic polypeptides III. Poly-l-lysine and poly-l-histidine in five salt solutions

Ifft

Pedersen

Fujita

et al. 1978

Carlsberg Res. Commun.

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“…(2)- (4) that numerical and iterative computational techniques are needed to describe the various distributions and unknown parameters.…”

Section: Methodsmentioning

confidence: 99%

“…These methods are described in a previous paper. 2 Accounting for pressure effects that alter the composition gradient involves an additional expression for pressure, and alters the expression for the density gradient represented by Eq. (1).…”

Section: Theorymentioning

confidence: 99%

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Effects of pressure on the composition density distribution in the ultracentrifuge

Sharp

Ifft

1982

Biopolymers

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SynopsisThe effects of pressure on the composition density distribution in a binary density gradient at sedimentation equilibrium in the analytical ultracentrifuge are rigorously examined. A computer algorithm is described for the necessary iterative computations. The pressure effect is found to be significant in runs where a long column length, high angular velocity, and a salt with a high pressure correction coefficient are simultaneously employed. Such conditions are sometimes encountered in current studies in which high precision is required to measure the compressibility of proteins.

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Density gradient proportionality constants, density distributions, and pressure effects for three salt solutions

Sharp¹,

Ifft²

1979

Biopolymers

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SynopsisEarlier determinations of density gradient proportionality constants p0, density distributions p ( r ) , and the effect of pressure on density gradients in the analytical ultracentrifuge have been of limited precision and usefulness in the study of proteins and polypeptides. Reasons for these difficulties are that numerous intermediate relationships were required in the calculations, and the density ranges studied were generally above 1.2 g/ml. Relations are derived in the present paper to directly compute $ ( p ) values and @J'(p) values from the original data without any intermediate expansions or approximations. Data are presented for CsCl, CsBr, and Cs2SO4 and compared with literature values. Density distributions are computed for all three salts under a wide variety of experimental conditions of density, column length, and angular velocity. These values of p ( r ) and re are obtained by a numerical iterative technique. Values obtained by this new method are compared with values obtained using closed-form expressions. The effects of pressure on the composition density gradient for the three salts given above are calculated and found to be significant for CszS04 solutions.

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Compressibility studies of three proteins in CsCl solutions in the analytical ultracentrifuge

Cited by 3 publications

References 6 publications

Buoyant and potentiometric titrations of synthetic polypeptides III. Poly-l-lysine and poly-l-histidine in five salt solutions

Buoyant and potentiometric titrations of synthetic polypeptides III. Poly-l-lysine and poly-l-histidine in five salt solutions

Effects of pressure on the composition density distribution in the ultracentrifuge

Density gradient proportionality constants, density distributions, and pressure effects for three salt solutions

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