ISOLATION AND DETERMINATION OF NON-DIFFUSIBLE SIALOFUCOHEXOSAMINOGLYCANS DERIVED FROM BRAIN GLYCOPROTEINS AND THEIR ANATOMICAL DISTRIBUTION IN BOVINE BRAIN

Abstract— Glycoproteins in brain tissue were assayed by determining the amount of N-acetylneuraminic acid (NANA), hexosamine, hexose, and fucose present in glycopeptides released by the proteolytic action of papain on the defatted protein residue that remains after treatment of the sample with chloroform-methanol (2:1 and 1:2, v/v). Diffusible and non-diffusible glycopeptides (sialofucohexosaminoglycans) were released by proteolysis. The procedure demonstrated that successive treatment of brain tissue with chloroform-methanol (2:1, v/v) and chloroform-methanol (1:2, v/v) removed all of the gangliosides present in the tissue. A 1 hr autolysis of rat brain tissue had no effect on the amount of glycopeptides recovered from the tissue. The carbohydrate composition of the non-diffusible sialofucohexosaminoglycans was also unaffected. Areas of the brain that are enriched in neuronal cell bodies contained a higher concentration of gangliosides and glycoproteins than areas that consist largely of myelinated fibre tracts. On the other hand, there was a greater concentration of glycoprotein relative to that of gangliosides in areas that consist predominately of myelinated fibre tracts and glia than in areas enriched in neuronal cell bodies. The concentration of non-diffusible sialofucohexosaminoglycans in whole bovine brain was less than that in whole rat brain. The non-diffusible sialofucohexosaminoglycans from whole bovine brain contained less fucose and NANA per mole of hexosamine and hexose than non-diffusible sialofucohexosaminoglycans isolated from whole rat brain. The non-diffusible sialofucohexosaminoglycans isolated from bovine cerebral white matter were lower in fucose and NANA content per mole of hexose and hexosamine than those isolated from other brain areas. It is suggested that the fucose and NANA content of the non-diffusible sialofucohexosaminoglycans associated with myelinated axons and (or) glia is less than that of the non-diffusible sialofucohexosaminoglycans associated with the nerve cell body.