The glycans of soybean peroxidase.
Soybean hull peroxidase (SBP, E.C. 1.11.1.7), an anionic glycoprotein, was found to contain 18.2% carbohydrate with the average composition: 2 mol GlcNAc, 3.3 mol Man, 0.9 mol Fuc, and 0.7 mol Xyl. The oligosaccharides of SBP, after release with glycopeptidase A, were investigated by a combination of high pH anion exchange chromatography with pulsed amperometric detection, methylation analysis and matrix assisted laser desorption/ionization-time-of-flight mass spectrometry. The structure of the major oligosaccharide, accounting for 60 to 65% of the total, is Man alpha 1-->6(Man beta 1-->3)(Xyl beta 1-->2)Man beta 1-->4GlcNAc beta 1-->4(Fuc alpha 1-->3)GlcNAc. A further 20 to 25% of the released oligosaccharides belong to the (Xyl)xManm(Fuc)fGlcNAc2 (m = 2, 4, 5, 6; f = 0 or 1, x = 0 or 1) family. The rest of the oligosaccharides were of the high-mannose type. Investigation of the six tryptic fractions containing carbohydrate revealed considerable heterogeneity in the N-linked oligosaccharides present in each fraction. The major glycan (4, Table III) was present in each fraction. Two of the fractions contained the major part of the high-mannose type glycans, ManmGlcNAc2 (m = 5-9), the major species being Man7GlcNAc2. The other four fractions contained mainly members of the (Xyl)xManm(Fuc)fGlcNAc2 (m = 2, 4, 5, 6; f = 0 or 1; x = 0 or 1) family. Methylation analysis of the holo- and apo-SBP provide support for the structures proposed for the oligosaccharides as well as for the heterogeneity of the glycopeptide fractions.
Gray
J S
JS
Department of Biochemistry, College of Medicine, University of Iowa, Iowa City 52242, USA.
Yang
B Y
BY
Hull
S R
SR
Venzke
D P
DP
Montgomery
R
R
D000581:Amidohydrolases / Q000378:metabolism; D002240:Carbohydrate Sequence; D002852:Chromatography, Ion Exchange; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008745:Methylation; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009844:Oligosaccharides / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D010449:Peptide Mapping; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D009195:Peroxidase / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D011134:Polysaccharides / Q000032:analysis* / Q000737:chemistry; D013025:Glycine max / Q000201:enzymology*; D014357:Trypsin / Q000378:metabolism
D006023:Glycoproteins; D009844:Oligosaccharides; D011134:Polysaccharides; D009195:Peroxidase; D014357:Trypsin; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase