Effect of modification of carbohydrate component on properties of glucoamylase

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Abstract
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.