Hemoglobin sedimentation coefficient

Human hemoglobin, for example, has a sedimentation coefficient of 4.48 S and a diffusion coefficient of 6.9 10 m2 s l in aqueous solution at 20°C. The density of this material is 1.34 g cm -3. Substituting these values into Equation (34) shows the particle mass to be... 

Sedimentation, used in conjunction with diffusion measurements, has been used for the determination of the molecular weights of macromolecules. At 20°C in a dilute aqueous solution, the sedimentation coefficient of hemoglobin, density 1.33 g/cm3, is 4.3 x 10"13 s. Its diffusion coefficient is 6.9 x 10 cm2/s. Calculate the molecular weight. How is this result affected by the hydration shell ... 

A slow mover. Tropomyosin, a 93-kd muscle protein, sediments more slowly than does hemoglobin (65 kd). Their sedimentation coefficients are 2.6S and 4.3 IS, respectively. Which structural feature of tropomyosin accounts for its slow sedimentation ... 

Rod-shaped molecules have larger frictional coefficients than do spherical molecules. Because of this, the rod-shaped tropomyosin has a smaller (slower) sedimentation coefficient than does the spherical hemoglobin, even though it has a higher molecular weight. 

Fig, 5 Isokinetic binding sedimentation of T3 receptors from oligodendrocytes and astrocytes. The receptors were extracted from nuclei of rat oligodendroglial and astroglial cells after 30 and 24 days in culture, respectively, with 0.4 M KCl and labelled in vitro with L-[ I]T3 in the absence ( -— ) or presence (O—O) of an excess of non-radioactive T3. The arrows represent the position of hemoglobin which has a sedimentation coefficient 4 3 S and was used as an internal marker (from Yusta et al.. Endocrinology 122 in press (1988) (71). With permission). 

The sedimentation coefficient of a sample of human hemoglobin in water is equal to 4.48 svedberg at 20°C, and its density is 1.335 g mL . The density of water at this temperature is equal to 0.998 g mL . Use the value of the diffusion coefficient from Example 10.16 to determine the molar mass of hemoglobin. 

The diffusion coefficient of horse heart myoglobin in water at 20°C is equal to 1.13 x 10 ° m s, and its sedimentation coefficient is equal to 2.04 svedberg. Assume that its density is equal to that of hemoglobin,... 

EXAMPLE 2.4 Solvation and Ellipticity of Human Hemoglobin from Sedimentation Data. The diffusion coefficient of the human hemoglobin molecule at 20°C is 6.9 10 11 m2 s "1. Use this value to determine f for this molecule. Evaluate f0 for hemoglobin using the particle mass calculated in Equation (35). Indicate the possible states of solvation and ellipticity that are compatible with the experimental flfQ ratio. 

---