Physical properties of the bovine encephalitogenic protein; molecular weight and conformation.

TLDR: The highly basic encephalitogenic protein isolated from bovine spinal cord was studied by various physicochemical methods to establish an understanding of its role in brain development.

Abstract: — The highly basic encephalitogenic protein isolated from bovine spinal cord was studied by various physicochemical methods: 1 The molecular weight was determined by sedimentation equilibrium, by calculation from the data on sedimentation coefficients and intrinsic viscosities, by measurement of intrinsic viscosity in the presence of concentrated guanidine hydrochloride (according to the method of Tanford, Kawahara and Lapanie, 1967), and by exclusion chromatography on Sephadex G-100 columns. All values obtained were in good agreement and indicated a molecular weight of approximately 18,000–20,000. 2 Studies of sedimentation velocities in the presence and absence of 6 m-guanidine-HCl indicated that there was a significant difference in the values of sedimentation coefficients. 3 The same conditions were applied to the measurements of viscosity; the difference was small but significant. These findings and the magnitude of the intrinsic viscosity suggested that this protein was in a disordered configuration. From these data, it is concluded that the protein was apparently monodispersed, in the presence or absence of the denaturing agent. This protein behaved like a polyelectrolyte in neutral aqueous solution. 4 The measurements of optical rotatory dispersion also confirmed that this protein existed in a disordered configuration.