Effect of modification of carbohydrate component on properties of glucoamylase

• Published in: FEBS letters 1993-01, Vol.316 (2), p.157-160
• Main Authors: Neustroev, K.N., Golubev, A.M., Firsov, L.M., Ibatullin, F.M., Protasevich, I.I., Makarov, A.A.
• Format: Article
• Language: English
• Subjects: 1-Deoxynojirimycin - chemistry; alpha-Mannosidase; Aspergillus - enzymology; Carbohydrate Metabolism; Carbohydrate Sequence; Carbohydrates - chemistry; Deglycosylation; Enzyme Stability; Glucan 1,4-alpha-Glucosidase - chemistry; Glucan 1,4-alpha-Glucosidase - metabolism; Glucoamylase; Glycoprotein; Glycosylation; Hot Temperature; Hydrogen-Ion Concentration; Mannosidases - chemistry; Molecular Sequence Data; Protein Conformation; Thermodynamics
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(93)81206-F

In this study, we investigated enzymatic deglycosylation of glucoamylase from Aspergillus awamori X 100/D27, a glycoprotein which has two N-linked and about forty short mannose-bearing O-linked sugars per molecule. O-Linked sugars were modified by treatment with α-mannosidase and N-linked sugars were removed using endo-β- N-acetylglucosaminidase F. Analysis ofconformational changes following deglycosylation suggests that O-linked sugars essentially contribute to the stabilization of glucoamylase domains. Modification of the carbohydrate component by adding 1-deoxymannojirimycin to the culture medium induced inhibition of α-mannosidases involved in the processing, leading to a more complete glycosylation and, consequently, to a higher stability of the enzyme.