Model particle size distribution, protein

Fisher, R. R. 1987. Protein precipitation with acids and polyelectrolytes The effects of reactor conditions and models of the particle size distribution. Ph.D. Thesis. Iowa State University, 165 pp. 

Figure 4.15 Particle size distribution of protein aggregate in a continuous stirred-tank reactor comparison of model with experimental data. 0.15kg/m A, 300kg/m O, 25.00kg/m. [From The Formation and Growth of Protein Precipitates in a Continuous Stirred-Tank Reactor, C.E. Glatz, M. Hoare, and J. Landa-Vertiz (1987), AIChE J. 32(7), pp. 1196-1204. Reproduced by permission of the American Institute of Chemical Engineers. 1987 AIChE.]...

Understandably, arguments offered by Sjostrand to explain this new arrangement differ from those previously used to justify the regularly beaded model. The main point is that the size range of particles approximately corresponds to the size range of mitochondrial protein molecules. Rather, the sizes of odd-shaped particles were compared to sizes of protein molecules assumed to be spherical (although most of the mitochondrial protein could be in the j8-confor-mation Wallach et al., 1969). The overall particle size distribution was not, however, compared to the compositional molecule size distribution of the membrane. 

Figure 2. Particle (number) size distributions for isoelectrically precipitated soy protein showing the effects of shear rate and protein concentration. Points are experimental data curves are the model fit using Equation 12. Shear rates A, 417 s l ...

FIGURE 6.19 The size distributions of pores filled by unfrozen water for (a) aqueous suspension of A-300 and the PSD calculated on the basis of the nitrogen adsorption/desorption isotherm (with the model of voids between spherical particles) (b) 0.15 mol NaCl or HPF solution at 1.25 and 2.5 wt% and (e) HPF/A-300 at different concentrations of protein and siliea. (Adapted with kind permission from Springer Seience+Business Media Cent. Eiir. J. Chem., Interaction of fibrinogen with nanosilica, 5, 2007, 32-54, Rugal, A.A., Gun ko, V.M., Barvinchenko, V.N., Turov, W., Semeshkina, T.V., and Zarko, V.I.)... 

Another microscopic technique is to freeze the specimen and then fracture it with a knife. A knife cutting through the frozen specimen splits the membrane down the middle, exposing the inside of the bilayer (fig. 17.13a). If the Davson-Danielli model for membrane structure were correct, the two exposed surfaces would be featureless. However, electron micrographs of metallic casts of such samples reveal surfaces studded with particles of various sizes (fig. 17.13(f)- Additional studies indicate that these particles are proteins that are deeply embedded in the membrane. The particles seen on the inner and outer leaflets of the bilayer usually differ in size and distribution because of an asymmetrical disposition of the proteins across the bilayer. 

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