Isolation and partial characterization of the major proteins of rabbit sciatic nerve myelin

The P 0, P 1, and P 2 proteins were isolated from rabbit sciatic nerve and demonstrated to have molecular weights of 30,000, 18,200, and 12,000, respectively, by polyacrylamide disk gel electrophoresis in the presence of sodium dodecyl fulfate. The P 1 protein characterized by peptide mapping, optical rotatory dispeorsion and encephalitogenic activity appears to be quite similar to the CNS myelin basic protein. The P 2 protein is distinctly different from the P 1 protein as characterized by peptide mapping and optical rotatory dispersion. It appears to have a distinct secondary structure, predominantly of β-configuration. The P 0 protein is distinctly different from either of the basic proteins, especially with respect to its marked insolubility in aqueous solutions. It contains more than 1.0 mole of hexosamine which is not present in either the P 1 or P 2 protein. Both the P 0 and P 2 proteins failed to produce any evidence of experimental allergic encephalomyelitis or neuritis when injected into guinea pigs or monkeys. In contrast, the P 1 protein produces experimental allergic encephalomyelitis in both species.