Identification of glycosaminoglycans in nerve terminals.

Synaptosomes were prepared using sucrose and Ficoll density-gradient-centrifugation procedures. Extraction of lipid-free material from both preparations with guanidinium chloride together with papain treatment released hexuronic-containing fractions. The glycosaminoglycan fractions (C1, C2, and C3) were isolated after ion-exchange chromatography. Chemical studies identified fraction C1 as a chondroitin sulphate proteoglycan whereas fractions C2 and C3 were characterised as hyaluronic acid and heparan sulphate. The relative yields of glycosaminoglycans (as compared with brain mitochondria) strongly suggest that these macromolecules form an integral component of nerve endings. The possible role of glycosaminoglycans in synaptosomes is also discussed.