Characterization of myelin basic protein charge isomers from adult mouse brain.

ADULT mouse MBP charge isomers (C1 or component 1, C2 or component 2, etc.) were purified from an acid soluble brain protein fraction by cation exchange chromatography. They were characterized by their elution profiles, their migration rates in alkaline-urea gels and by SDS-PAGE. Mouse C1 and C2 were both 14 kD in size, while C3, C4 and C5 consisted of the 18.5, 17 and 14 kD isoforms. Comparison of mouse and human MBP charge isomers showed that they were similar in that they both showed extensive charge heterogeneity, but different in that mouse MBP charge isomers were more cationic than their human counterparts. Finally, a possible explanation for the presence of the 14 kD MBP isoform in mouse myelin was suggested.