Structural studies on the O-glycosidically linked carbohydrate chains of glucoamylase G1 from Aspergillus niger.
Glucoamylase G1 from Aspergillus niger contains an unusual type of carbohydrate-protein linkage, involving mannose O-glycosidically linked to serine and threonine. The majority of the neutral oligosaccharides of glucoamylase G1 are located in a region of about 70 amino acid residues which carries about 35 oligosaccharide units [(1983) Carlsberg Res. Commun. 48, 517-527]. Structural analysis was performed on the O-linked carbohydrates of a tryptic fragment from glucoamylase G1 comprising the segment characterized by a high degree of glycosylation. The carbohydrate structures released by trifluoroacetolysis were elucidated using sugar analysis, methylation analysis, mass spectrometry, chromium trioxide oxidation, digestion with alpha-mannosidase and 1H-NMR spectroscopy. The following structures could be identified. (formula; see text)
D001234:Aspergillus niger / Q000201:enzymology*; D002241:Carbohydrates / Q000032:analysis; D055598:Chemical Phenomena; D002621:Chemistry; D002857:Chromium; D017608:Chromium Compounds; D005087:Glucan 1,4-alpha-Glucosidase / Q000302:isolation & purification*; D005959:Glucosidases / Q000302:isolation & purification*; D006027:Glycosides / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D008361:Mannosidases; D013058:Mass Spectrometry; D008745:Methylation; D010084:Oxidation-Reduction; D014269:Trifluoroacetic Acid; D043323:alpha-Mannosidase
D002241:Carbohydrates; D017608:Chromium Compounds; D006027:Glycosides; D002857:Chromium; C028801:chromium trioxide; D014269:Trifluoroacetic Acid; D005959:Glucosidases; D008361:Mannosidases; D043323:alpha-Mannosidase; D005087:Glucan 1,4-alpha-Glucosidase