Aggregated human serum immunoglobulin A1 induced by neuraminidase treatment had a lower number of O-linked sugar chains on the hinge portion.
A part of human serum immunoglobulin A1(IgA1) was aggregated by treatment with neuraminidase. Aggregated IgA1 was separated from non-aggregated IgA1 by gel permeation chromatography. The prepared asialo-hinge glycopeptide (asialo-HGP) from both IgA1 subfractions was treated with beta-galactosidase to determine the number of beta-linked sugar chains attached on the hinge region. Removal of the galactose residue from asialo-HGP resulted in the HPLC separation of three major peaks. MALDI-TOFMS analysis of the glycopeptides also indicated the presence of three HGP components with three, four and five N-acetylgalactosamine (GalNAc) residues, respectively. Comparison of their relative content among the glycopeptide components showed a higher content of the HGP component with a lower number of GalNAc residues on aggregated IgA1. Thus, asialo-HGP prepared from aggregated IgA1 induced by neuraminidase treatment had an incomplete core structure of O-linked oligosaccharides. Especially, the result suggested that the reduced number of the attached O-linked oligosaccharides on IgA1 take part in phenomena such as self-aggregation of asialo-IgA1.
Iwase
H
H
Department of Biochemistry and Medicine, School of Medicine and Nursing, Kitasato University, Kanagawa, Japan. iwaseh@med.kitasato-u.ac.jp
Tanaka
A
A
Hiki
Y
Y
Kokubo
T
T
Sano
T
T
Ishii-Karakasa
I
I
Toma
K
K
Kobayashi
Y
Y
Hotta
K
K
D000595:Amino Acid Sequence; D002240:Carbohydrate Sequence; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood / Q000737:chemistry* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009439:Neuraminidase / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D007070:Immunoglobulin A; D010446:Peptide Fragments; D009439:Neuraminidase