Basic Proteins of Rodent Peripheral Nerve Myelin: Immunochemical Identification of the 21.5K, 18.5K, 17K, 14K, and P2 Proteins

: Proteins in peripheral nervous system and central nervous system myelin and homogenates of sciatic nerve and brain from young and adult mice and rats were characterized with affinity‐purified anti‐P2 and anti‐myelin basic protein sera after electrophoretic transfer from sodium dodecyl sulfate‐polyacrylamide gels to nitrocellulose sheets. Using this method we have identified a component of rodent peripheral nervous system myelin as P2 protein. Peripheral nervous system myelin also showed the presence of four basic proteins in addition to P2 protein. These were found to be analogous to the 14, 17, 18.5, and 21.5K species found in the central nervous system myelin. A number of high‐molecular‐weight proteins were also detected with anti‐myelin basic protein serum in peripheral nervous system, as well as central nervous system myelin. In addition, we report the presence of a high‐molecular‐weight P2 cross‐reactive protein in rodent brain stem homogenates, but not in central nervous system myelin.