Purification and chemical characterization of a W2 protein from brain myelin

Starting from a pellet of beef brain myelin insoluble in chloroform/methanol (2:1, vol/vol)(Wolfgram protein fraction), a pure W2 protein with apparent molecular weight of 52,000 was isolated by a simple preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis method. A comparative chemical analysis was carried out between purified W2 and a standard tubulin. Glutamic acid and arginine were the N-terminals detected. Similar peptide maps and amino acid composition were also found in both proteins. Immunological cross-reactivity was detected when W2 protein was tested against antitubulin serum. These results suggest that W2 protein could have a tubulin-like protein nature that is associated with the myelin membrane and could play a role in the myelination process.