Structural study on the carbohydrate moiety of human placental alkaline phosphatase.
Alkaline phosphatase purified from human placenta contains a single asparagine-linked sugar chain in one molecule. The sugar chain was quantitatively liberated as radioactive oligosaccharides from the polypeptide moiety by hydrazinolysis followed by N-acetylation and NaB3H4 reduction, and separated by paper electrophoresis into one neutral and two acidic fractions. By a combination of sequential exoglycosidase digestion and methylation analysis, the structures of oligosaccharides in the neutral fraction were confirmed to be as follows: Gal beta 1----4GlcNAc beta 1----2Man alpha 1----6(Gal beta 1----4GlcNAc beta 1----2Man alpha 1----3)Man beta 1----4GlcNAc beta 1----4(+/- Fuc alpha 1----6)GlcNAc. The acidic oligosaccharide fractions were mixtures of mono- and disialyl derivatives of the neutral fraction. All the sialic acid residues of the sugar chains occur as the NeuAc alpha 2----3Gal group. In the case of monosialyl derivatives, the N-acetylneuraminic acid was exclusively linked to the Man alpha 1----3 arm.
Endo
T
T
Department of Biochemistry, University of Tokyo.
Ohbayashi
H
H
Hayashi
Y
Y
Ikehara
Y
Y
Kochibe
N
N
Kobata
A
A
D000469:Alkaline Phosphatase / Q000302:isolation & purification*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005260:Female; D006026:Glycoside Hydrolases; D006801:Humans; D007425:Intracellular Membranes / Q000201:enzymology; D008861:Microsomes / Q000201:enzymology*; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000032:analysis*; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy
D009844:Oligosaccharides; D000469:Alkaline Phosphatase; D006026:Glycoside Hydrolases