Chromatographic Fractionation of Myelin Basic Protein

Guinea pig myelin basic protein has been chromatographed on carboxymethylcellulose at alkaline pH to yield five purified components, each of which was shown to be identical with one of the several components which have previously been observed electrophoretically at alkaline pH. Each purified chromatographic component was stable upon electrophoresis at alkaline pH. No differences in molecular size were detected among the chromatographic components when examined by gel filtration under conditions approximating those of alkaline pH electrophoresis or chromatography. In contrast to their markedly different electrophoretic mobilities at alkaline pH, each component when subjected to electrophoresis at acid pH displayed essentially the same mobility. No significant differences among the different chromatographic forms were detected with regard to encephalitogenic activity or amino acid composition. Analyses for methylarginine showed that each chromatographic form contained approximately the same amount per mole of protein of NGmonomethyland NC, N’o-dimethylarginine. No other methylated basic amino acids, including NG, NG-dimethylarginine, were present.