A monosaccharide is bound to the sodium pump alpha-subunit.
Biochemistry
; 31(43): 10465-70, 1992 Nov 03.
Article
en En
| MEDLINE
| ID: mdl-1329950
ABSTRACT
We have recently reported that the Na pump alpha-subunit has cytosolic-oriented oligosaccharides which were sensitive to cleavage by an enzyme specific for hydrolysis of N-linked glycans [Pedemonte et al. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 9789-9793]. We now describe experiments that characterize the saccharides and further substantiate our previous findings. Bovine milk galactosyltransferase has been used in conjunction with radiolabeled UDP-galactose to label N-acetylglucosamine residues on the protein. The Na pump alpha-subunit contains some O-linked carbohydrates; however, the bulk (> 80%) of the radioactivity was found in oligosaccharides sensitive to peptideN-glycosidase F degradation but not to alkaline hydrolysis. Alkaline hydrolysis produced degradation of the protein, and the [3H]Gal radiolabeled carbohydrates remained bound to peptides and were released by subsequent peptide N-glycosidase F treatment. The exogenously galactosylated sugars cleaved by the glycosidase were analyzed by liquid chromatography and had elution volumes identical to a galactose-N-acetylglucosamine disaccharide standard. Since the galactose was exogenously added, we propose that the N-linked glycans on the alpha-subunit of the Na pump are composed of a single sugar residue, which is probably N-acetylglucosamine.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
ATPasa Intercambiadora de Sodio-Potasio
/
Monosacáridos
Límite:
Animals
Idioma:
En
Revista:
Biochemistry
Año:
1992
Tipo del documento:
Article