Analytical ultracentrifugation ultracentrifuge

Apart from tliese mainstream metliods enabling one to gain a comprehensive and detailed stmctural picture of proteins, which may or may not be in tlieir native state, tliere is a wide variety of otlier metliods capable of yielding detailed infonnation on one particular stmctural aspect, or comprehensive but lower resolution infonnation while keeping tlie protein in its native environment. One of tlie earliest of such metliods, which has recently undergone a notable renaissance, is analytical ultracentrifugation [24], which can yield infonnation on molecular mass and hence subunit composition and their association/dissociation equilibria (via sedimentation equilibrium experiments), and on molecular shape (via sedimentation velocity experiments), albeit only at solution concentrations of at least a few tentlis of a gram per litre. 

Schuster T M and Toedt J M 1996 New revolutions in the evolution of analytical ultracentrifugation Curr. Opinion Ceii. Bioi. 6 650-8... 

FIGURE 9.23 Analysis of ultrahigh poly(acrylamjde). MW 48 million by analytical ultracentrifugation. Eluent 0.1 M Na2SO<. Flow rate 0.3 ml/min. Columns PSS Suprema 30000, 20 /tim, 8 x 300 mm. Oven temp 30°C. Detector Rl. Standards PSS polyacrylamide standards. 

Analytical ultracentrifugation (AUC) Molecular weight M, molecular weight distribution, g(M) vs. M, polydispersity, sedimentation coefficient, s, and distribution, g(s) vs. s solution conformation and flexibility. Interaction complex formation phenomena. Molecular charge No columns or membranes required [2]... 

Harding SE, Rowe AJ, Horton JC (eds) (1992) Analytical Ultracentrifugation in Biochemistry and Polymer Science. Royal Society of Chemistry, Cambridge, UK... 

Analytical Ultracentrifugation in Biochemistry and Polymer Science. Royal Society... 

Minton AP (1994) In Schuster TM, Laue TM (eds) Modern Analytical Ultracentrifugation. Birkhauser, Boston, 81... 

With this relationship for all samples was calculated from ninh This M is used for evaluating the reaction data. The ultracen rifuge (u.c measurements were carried out in a Spinco model E analytical ultracentrifuge, with 0.4% solutions in 90% formic acid containing 2.3 M KCl. By means of the sedimenta- ion diffusion equilibrium method of Scholte (13) we determine M, M and M. The buoyancy factor (1- vd = -0.086) necessary for tSe calculation of these molecular weights from ultracentrifugation data was measured by means of a PEER DMA/50 digital density meter. 

Techniques which seem less suitable for routine size analysis are (1) analytical ultracentrifugation combined with a Schlieren optical system (Mason and Huang, 1978 Weder and Zumbuehl, 1984) (2) the sedimentation field flow fractionation (SFFF) technique to separate heterogeneous dispersions (e.g., Kirkland et al., 1982). 

Techniques for study of higher orders of protein stmcture include x-ray crystallography, NMR spectroscopy, analytical ultracentrifugation, gel filtration, and gel electrophoresis. 

The membrane-bound preparation from kidney is easily solubilized in non-ionic detergent and analytical ultracentrifugation shows that the preparation consists predominantly (80 85%) of soluble af units with 143000 [28]. The soluble a)S unit maintains full Na,K-ATPase activity, and can undergo the cation or nucleotide induced conformational transitions that are observed in the membrane-bound preparation. A cavity for occlusion of 2K or 3Na ions can be demonstrated within the structure of the soluble a)S unit [29], as an indication that the cation pathway is organized in a pore through the aji unit rather than in the interphase between subunits in an oligomer. 

Hensley P. Defining the structure and stability of macromolecular assemblies in solution the re-emergence of analytical ultracentrifugation as a practical tool. Structure 1996 4 367-373. 

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