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Chapter 10 Lipids S-119
(c) This analysis is similar to that used by Sanger to determine the amino acid sequence of
insulin. The analysis of each fragment reveals only its composition, not its sequence,
but because each fragment is formed by sequential removal of one sugar, we can draw
conclusions about sequence. The structure of the normal asialoganglioside is ceramide–
glucose–galactose–galactosamine–galactose, consistent with Box 10–2 (excluding
Neu5Ac, removed before hydrolysis). 
(d) The Tay-Sachs asialoganglioside is ceramide–glucose–galactose–galactosamine, consis-
tent with Box 10–2. 
(e) The structure of the normal asialoganglioside, GM1, is: ceramide–glucose (2 —OH
involved in glycosidic links; 1 —OH involved in ring structure; 3 —OH (2,3,6) free for
methylation)– galactose (2 —OH in links; 1 —OH in ring; 3 —OH (2,4,6) free for
methylation)–galactosamine (2 —OH in links; 1 —OH in ring; 1 —NH2 instead of 
an —OH; 2 —OH (4,6) free for methylation)–galactose (1 —OH in link; 1 —OH in ring;
4 —OH (2,3,4,6) free for methylation).
(f) Two key pieces of information are missing: What are the linkages between the sugars?
Where is Neu5Ac attached?
Reference
Svennerholm, L. (1962) The chemical structure of normal human brain and Tay-Sachs gangliosides. Biochem. Biophys. Res. Comm.
9, 436–441.
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