Novel oligomannose-type sugar chains derived from glucose oxidase of Aspergillus niger

The primary structure of the N-linked sugar chains of glucose oxidase from Aspergillus niger was investigated. These sugar chains were released from the polypeptide backbone by hydrazinolysis, and the reducing ends of the sugar chains were pyridylaminated. HPLC of the pyridylamino sugar chains with an amide-silica column showed at least seven sugar chain peaks. Chemical and exoglycosidase, digestion and 400MHz ¹H-NMR studies of the sugar chains of lower molecular weight showed that these were novel oligomannose-type sugar chains, (Man)_5-7(GlcNAc)₂, with the structure: ±Manα1→3Manα1→3(Manα1→6)Manα1→6 (±Manα1→3Manα1→3)Manβ1→4GlcNAcβ1→4GlcNAc.