Simultaneous Separation and Purification of Neurofilament and Glial Filament Proteins from Brain

Abstract

Neurofilaments (NF) and glial filaments (GF) were purified from bovine brain by the axonal flotation method, followed by hydroxylapatite chromatography in 8 M urea. The proteins were competent to reassemble into intermediate filaments with removal of the denaturant, and reassembly was used as the final step in the purification of the filament proteins. The reassembly was dependent on ionic strength and pH. This dependence was greater for neurofilaments than for the glial filaments. The NF and GF preparations were not contaminated with each other by their gel electrophoretic profile and their immunological distinctness. The filament proteins can be obtained in high yield and remain in solution if the urea is removed by dialysis against a low ionic strength buffer. They can provide a source for further biochemical studies.