Sulphated glycoproteins in synaptosomes.

Synaptosomes from sheep brain were incubated with Na2(35)SO4. After lysis at least twelve 35S-containing proteins were identified in the synaptosomal soluble fraction with molecular weights ranging between 13,000 and 150,000. Extraction of the particulate fraction with SDS/urea revealed a further eight [35S]proteins with 27,000-140,000 molecular weights. A glycopeptide rich in fucose, sialic acid, N-acetylglucosamine and galactose was isolated from papain treated synaptosomal material. Over half of the hexosamine and neutral sugar residues were found to contain 35S. These findings suggest that sulphation of glycoproteins can occur in isolated nerve terminals.