The structure of the asparagine-linked sugar chains of bovine brain ribonuclease.
The asparagine-linked sugar chains of bovine brain ribonuclease were quantitatively released as oligosaccharides from the polypeptide backbone by hydrazinolysis. After N-acetylation, they were converted into radioactively-labeled oligosaccharides by NaB3H4 reduction. The radioactive oligosaccharide mixture was fractionated by ion-exchange chromatography, and the acidic oligosaccharides were converted into neutral oligosaccharides by sialidase digestion. The neutral oligosaccharides were then fractionated by Bio-Gel P-4 column chromatography. Structural studies of each oligosaccharide by sequential exoglycosidase digestion in combination with methylation analysis revealed that bovine brain ribonuclease showed extensive heterogeneity. It contains bi- and tri-antennary, complex-type oligosaccharides having alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-beta-D-Manp -(1----4)-beta-D- GlcpNAc-(1----4)-[alpha-L-Fucp-(1----6)]-D-GlcNAc as their common core. Four different outside oligosaccharide chains, i.e., beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----, alpha-Neu5Ac-(2----6)-beta-D- Galp-(1----4)-beta-D-GlcpNAc-(1----, alpha-Neu5Ac-(2----3)-beta-D-Galp-(1----4)- beta-D-GlcpNAc-(1----, and alpha-D-Galp-(1----3)-beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----, were found. The preferential distribution of the alpha-D-Galp-(1----3)-beta-D-Galp-(1----4)-beta-D-GlcpNAc group on the alpha-D-Manp-(1----6) arm is a characteristic feature of the sugar chains of this enzyme.
Katoh
H
H
Department of Microbiology, Hoshi College of Pharmacy, Tokyo, Japan.
Ohgi
K
K
Irie
M
M
Endo
T
T
Kobata
A
A
D000818:Animals; D001216:Asparagine; D001921:Brain / Q000201:enzymology*; D002240:Carbohydrate Sequence; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D006026:Glycoside Hydrolases; D008745:Methylation; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000032:analysis; D012260:Ribonucleases
D009844:Oligosaccharides; D001216:Asparagine; D012260:Ribonucleases; D006026:Glycoside Hydrolases