Enzyme activity of human central nervous system myelin

Following ultracentrifugation in sucrose and hypotonic exposure ('osmotic shock'), myelin fractions were prepared from homogenates of human centrum ovale obtained post-mortem. Non-specific esterase (NsE), succinic dehydrogenase and acid phosphatase activities were determined. One isolation procedure utilized aqueous sucrose solutions only. Other preparative technics involved addition of phosphate buffer (pH 6.6 or 8.0) or varying concentrations of calcium or magnesium ions to preparative media. The NsE activity of myelin increased greatly when electrolytes were included in these preparative solutions. Morphologic homogeneity and protein and lipid contents of myelin were similar whatever the isolation procedure.