The Calibration of Diffusion Membranes and the Calculation of Molecular Volumes From Diffusion Coefficients

Anson, M. L.; Northrop, John H.

doi:10.1085/jgp.20.4.575

Cited by 30 publications

(7 citation statements)

References 8 publications

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“…The temperature was determined with a Beckman thermometer calibrated against a Bureau of Standards thermometer. The diffusion ceils and the shells which hold them were similar to those previously described (1)(2)(3). The cell constants were obtained with n / l HC1 and confirmed with 0.5 per cent pepsin.…”

Section: Description Of Diffusion Apparatussupporting

confidence: 76%

“…Certain variables associated with the measurement of the sedimentation and diffusion coefficients were therefore cancelled out. For the measurement of the diffusion coefficient of DNA transforming activity, it was necessary because of the small diffusion coefficient of DNA to turn to the use of the Northrop-Anson porous disc method (1)(2)(3). This method has proved to be reliable for proteins of molecular weight 60,000, but the molecular weights of DNA are considerably greater and the asymmetry of the molecules is relatively enormous.…”

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confidence: 99%

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Studies on Transformations of Hemophilus influenzae

Goodgal

Herriott

1961

The Journal of General Physiology

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A B S T R A £I T T h e s e d i m e n t a t i o n a n d diffusion coefficients h a v e b e e n d e t e r m i n e dfor Hemophilus influenzae transforming activity and DNA using PSMabeled DNA.The methods employed the Spinco fixed boundary separation cell for measurements of the sedimentation coefficient and the Northrop-Anson diffusion cell to determine the diffusion coefficient. There was a very close correlation between the amount of DNA and transforming activity sedimented or diffused. The sedimentation coefficient (s20*), for both biological activity and DNA was 27 and the diffusion coefficient (D20.) 1 X 10 -8 cm2/sec. The molecular weight calculated from these coefficients gave a value of 16 million. There was no difference in the sedimentation coefficients for the two unlinked markers, streptomycin and erythromycin resistance, and the diffusion coefficients for single markers or the linked markers, streptomycin and cathomycin, were the same.

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Section: Description Of Diffusion Apparatussupporting

confidence: 76%

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confidence: 99%

Studies on Transformations of Hemophilus influenzae

Goodgal

Herriott

1961

The Journal of General Physiology

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“…An approximate estimate of the size and uniformity of the split products is conveniently obtained by measuring the diffusion coefficient of the digested material. The method of Northrop and Anson (1929) (see also Anson and Northrop, 1937) has been employed for this purpose.…”

Section: Increase In Ultraviolet Light Absorptionmentioning

confidence: 99%

Crystalline Desoxyribonuclease

Kunitz¹

1950

Journal of General Physiology

170

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A study was made of the enzymatic properties of crystalline desoxyribonuclease. The general effect of the crystalline enzyme on its specific substrate, thymus nucleic acid, was found to be essentially the same as described by previous workers for the digestive action of crude preparations of the enzyme. The digestive action consists mainly in splitting thymus nucleic acid into fragments approaching the size of tetranucleotides. The digested nucleic acid is diffusible through collodion or cellophane membranes and is non-precipitable with strong acid, alcohol, or proteins. The digestion of thymus nucleic acid by desoxyribonuclease is accompanied by the liberation of one atom equivalent of free acid per four atoms of nucleic acid phosphorus. Crystalline desoxyribonuclease acts very slowly, if at all, in the absence of magnesium (or manganese) ions. The optimal concentration of magnesium ion required increases with the increase in concentration of the substrate but is independent of the enzyme concentration. The optimal pH range for the action of crystalline desoxyribonuclease is 6.0 to 7.0. A study was made of the kinetics of the digestion of thymus nucleic acid as manifested mainly by the gradual formation of acid-soluble split products. At low concentrations of nucleic acid, the process approximates closely a reaction of the first order, the unimolecular constant being independent of the concentration of desoxyribonuclease in the digestion mixture. At relatively higher concentrations of substrate, however, the initial rate of reaction decreases rapidly with the increase in concentration of substrate, and the reaction as a whole is represented by non-symmetric S-shaped curves apparently too complicated for a simple rational interpretation.

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“…This is possible if (1) <s% = 0, in which case one is dealing with a monodisperse solution; {2) <ji « ci ; or (3) c2 « Ci . Case (2) implies that, as mentioned, at a given distance, x, the observed refractive-index gradient is due only to the first component and is zero for the second component. Case (8) implies merely that the concentration of the second component is altogether too small to give rise to a measurable refractive-index gradient.…”

Section: (B) Polydisperse Systemsmentioning

confidence: 86%

“…those of the two components. Such a comparison is made in table2 for the case in which the diffusion constant of the single substance, s/Do, is equal to ^^, The change in maximum ordinate is again expressed i v i d u a l n o t d i r e c t l y a s s o c i a t e d w i t h s c i t e i s p r o h i b i t e d .…”

mentioning

confidence: 99%

The Investigation of Proteins by Diffusion Measurements.

Neurath¹

1942

Chem. Rev.

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The Calibration of Diffusion Membranes and the Calculation of Molecular Volumes From Diffusion Coefficients

Cited by 30 publications

References 8 publications

Studies on Transformations of Hemophilus influenzae

Studies on Transformations of Hemophilus influenzae

Crystalline Desoxyribonuclease

The Investigation of Proteins by Diffusion Measurements.

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