The development of sedimentation equilibrium in the air-driven preparative ultracentrifuge has provided an independent, nonempirical method to characterize partially purified macromolecules within heterogeneous preparations, based on the equilibrium distribution of their biochemical or other specific activities as a function of radial distance in a centrifugal field. Since this method is based on a theoretical thermodynamic description of the system in sedimentation-diffusion equilibrium and is independent of molecular weight standards and zonal transport, the difficulties outlined in this chapter are effectively avoided. In addition, the method has opened this area of investigation to the extensive existing literature concerning the use of sedimentation equilibrium to determine the molecular weights and interactions of proteins in solution, which had been previously restricted to highly purified protein preparations detected optically in the analytical ultracentrifuge. This chapter illustrates that as the time required to approach to within a specific deviation from true sedimentation equilibrium is proportional to the square of this radial distance, 17 short distances are necessary for achievement of experimental sedimentation equilibrium within a reasonable time. Furthermore, the nonsectorial geometry of the tube walls initially creates convective transport of solute18 which contributes to achievement of experimental sedimentation equilibrium within 24 hr. Series: Methods in Enzymology (Book 117) Hardcover: 576 pages Publisher: Academic Press; 1 edition (December 12, 1985) Language: English ISBN-10: 0121820173 ISBN-13: 978-0121820176 Product Dimensions: 6 x 9 inches Link Download http://nitroflare.com/view/B38A482C28A51A3https://drive.google.com/drive/folders/1yLBzZ1rSQoNjmWeJTZ3WGQHg04L1
