Studies on myelin proteins in human peripheral nerve.

Abstract

The myelin fraction from human peripheral nerve was prepared. Two basic protein fractions (BF-P2 and PB) were isolated from acid extracts of the myelin fraction and three glycoproteins (BR-PO, PASII and Y protein) were purified from its acid-insoluble residue. In biochemical analysis the human BF-P2 protein (M.W.13,000) showed similar but not identical properties to bovine BF-P2 protein. The PB fraction was suggested to include the encephalitogenic CNS-BP (M.W.18,000) and another, new protein of similar molecular weight. Both the human BR-PO protein (M.W.28,000) and PASII protein (M.W.13,000) showed similar biochemical properties to the corresponding myelin proteins of bovine peripheral nerve, while they both are clearly different from other myelin proteins. Close relationship between the BR-PO protein and the Y protein (M.W.22,000) was suggested by amino acid analysis. Injection of the myelin fraction of bovine peripheral nerve with the complete adjuvant produced EAN while the CNS-BP induced EAE in laboratory animals. However, all three purified proteins, BF-P2, BR-PO and PASII, from bovine peripheral nerve myelin were inactive in inducing demyelinating diseases.