of Work: The work of the Section, aiming at development of predictably and optimally resolving automated electrophoretic separation physical characterization and isolation methods, is pursuing that aim at the present time in application to three technologies, i) capillary zone electrophoresis (CZE), ii) automated gel electrophoresis (HPGE) and iii) free-flow electrophoresis (FFE). i) It is being attempted to correlate the type, size and concentration of polymers in solution with resolution of particles differing in size and shape by CZE in order to rende such 'size separations' predictable. This has been achieved for particles of less than 30 nm diameter. In the particle size range 30-400 nm, resolution was found to improve in presence of polymers by less than one order of magnitude. In application to larger particles, band spreading in presence of polymers leads to a net loss of resolution. Polymer length in the semi-dilute concentration range does not affect resolution in the small particle size range. For larger particles, polymer length affects mobility variably as a function of ionic strength, shear rate, polymer relaxation time (rigidity) and presence of a 'depletion layer near the particle-polymer interface. ii) HPGE is of the greatest interest as a preparative method, in particular in application to subcellular-sized particles and to proteins prior to mass spectrometric characterization. Both applications have been made. The first stillposes instrumental problems, the latter the problem of providing fluorescently unlabeled protein or a removable fluorescent label. iii) The development of FFE to a 'quantitative' method is in progress under a CRDF grant in Moscow, Russia. iv) Membrane complexes containing immunoactive 'fusion proteins' in ghosts of the sea urchin egg cortical membrane have been pinpointed by gel electrophoresis conducted in weak, 'non-denaturing', detergents. A systematic study of the size and polypeptide composition of the immunoactive membrane components as a function of the type and concentration of nonionic detergent is in progress which takes advantage of the speed and economy of the miniaturized PhastSystem method. v) Gel electrophoresis and CZE have been applied to separate and characterize two forms of beta-amyloid peptide, one of which reacts with Congo Red and provides a tool for the early diagnosis of Alzheimer's disease.
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