[3 5S]Sulfate incorporation into myelin glycoproteins II. Peripheral nervous tissue

The in vivo incorporation of [^{3 5}S]sulfate, [³H]fucose and [³H]leucine into sciatic nerve myelin was investigated. Polyacrylamide gel electrophoresis of the proteins indicated that the ^{3 5}S-labeling of proteins occurred almost exclusively in the major myelin protein. A smaller myelin glycoprotein migrating just ahead of the major one was labeled with [³H]fucose but did not incorporate ^{3 5}S to a detectable extent. There was little or no ^{3 5}S associated with basic proteins on polyacrylamide gels when the proteins were extracted with chloroform/methanol. Fucose-labeled myelin glycoproteins were converted to glycopeptides by pronase digestion. The glycopeptides gave a single peak on Sephadex G-50 in which the ³H and ^{3 5}S coincided. The association of ^{3 5}S with glycopeptides was not caused by binding of sulfatide or free inorganic sulfate. This study shows that the major myelin protein in the sciatic nerve of the rat is glycosylated and sulfated.