This chapter discusses the criteria for distinguishing self-associations in velocity sedimentation. This chapter describes the criteria that may be applied to distinguish the following three cases; (1) true heterogeneity of the protein, or the existence of the protein in more than one state of stable aggregation; (2) rapidly reequilibrating self-association to polymers greater than a dimer; and (3) rapidly reequilibrating self-association mediated by a strongly binding small ligand. In true heterogeneity, the species of various molecular weights sediment according to its size, shape, and molecular weight. In rapidly reequilibrating self-association, when the polymerization is cooperative to an end product the pattern resolves into a bimodal one. Here, resolution of the schlieren pattern sets in immediately after separation from the meniscus. In ligand-mediated self-associations system, the self-association of a protein to a dimer or higher species is linked to the binding of one or more molecules of a small ligand during the polymerization reaction. The three cases discussed in this chapter are well illustrated on the self-association of tubulin under various circumstances. These examples clearly illustrate the application of the criteria for distinguishing among the three types of systems that give rise to bimodality in velocity sedimentation. These criteria can serve as powerful diagnostic tools to identify the type of aggregation which a given system is undergoing. Series: Methods in Enzymology Hardcover: 587 pages Publisher: Academic Press; Language: English ISBN-10: 0121820300 ISBN-13: 978-0121820305 Product Dimensions: 6 x 1.3 x 9 inches Link Download http://nitroflare.com/view/BD05308A4DE4E00https://drive.google.com/drive/folders/1yLBzZ1rSQoNjmWeJTZ3WGQHg04L1
