Structural study of the oligosaccharide moieties of sphingolipid activator proteins, saposins A, C and D obtained from the spleen of a Gaucher patient.
We have determined and compared the structures of the oligosaccharide moieties of saposin A, C and D purified from the spleen of a patient with Gaucher disease. These saposins, together with saposin B, are small glycoproteins, derived from separate domains of a single precursor, prosaposin, and are required for the lysosomal hydrolysis of various sphingolipids. The characteristic features of the oligosaccharide moieties of saposin A are (a) the predominance of a fucosylated trimannosyl core structure and (b) the occurrence of several different oligomannose-type and N-acetyllactosamine-type oligosaccharides. Saposin C contains (a) a predominance of oligomannose-type oligosaccharides and monoantennary oligosaccharides and (b) the presence of four different oligosaccharides having bisecting N-acetylglucosamine residues (found only in this saposin). Saposin D is distinguished by the occurrence of oligomannose-type oligosaccharides, which comprise nearly 90% of its total oligosaccharides. The possible reasons for the unique glycosylation of each saposin is discussed.
Ito
K
K
Department of Neurology, Nagoya University School of Medicine, Aichi, Japan.
Takahashi
N
N
Takahashi
A
A
Shimada
I
I
Arata
Y
Y
O'Brien
J S
JS
Kishimoto
Y
Y
D002240:Carbohydrate Sequence; D005776:Gaucher Disease / Q000378:metabolism*; D006023:Glycoproteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry*; D049231:Saposins; D013154:Spleen / Q000737:chemistry*
D006023:Glycoproteins; D009844:Oligosaccharides; D049231:Saposins