Structure of the glycopeptide storage material in GM 1 gangliosidosis. Sequence determination with specific endo- and exoglycosidases.

1. An endo-beta-galactosidase from Escherichia freundii, specific for the hydrolysis of desulfated keratan sulfate, quantitatively liberated a trisaccharide (Gal-GlcNAc-Gal) from a glycopeptide (Mr 1800) isolated from the liver of a patient with GM 1 (generalized) gangliosidosis. 2. The remaining glycopeptide was susceptible to sequential digestion with purified beta-N-acetylhexosaminidase and exo-beta-galactosidase from Jack Bean meal. 3. These and other studies established the structure of the stored glycopeptide to be:(see article) which probably represents the desulfated linkage region of skeletal keratan sulfate.