Abstract
A cytoplasmic enzyme from guinea pig brain was shown to transfer methyl groups from S-adenosylmethionine to only one of 19 arginine residues in the basic protein from human brain. The products were ω-N-monomethylarginine and ω-N,N'-dimethylarginine. These methylated arginines are adjacent to the main encephalitogenic determinant in the protein. Methylation may aid in the transfer of this region of the protein into the nonpolar environment within myelin and in maintaining the integrity of myelin.