Deglycosylation of glucoamylase from Aspergillus niger: Effects on structure, activity and stability

A comparative structure–function study was performed to establish possible roles of carbohydrates in stabilization of glycoproteins, using glucoamylase (GA) as a model system. In addition to kinetic properties, stability toward elevated temperatures, extremes of pH, high salt concentrations together...

Full description

Saved in:
Bibliographic Details
Published in:Biochimica et biophysica acta 2005-06, Vol.1750 (1), p.61-68
Main Authors: Jafari-Aghdam, Javad, Khajeh, Khosro, Ranjbar, Bijan, Nemat-Gorgani, Mohsen
Format: Article
Language:English
Subjects:
Aggregation
Aspartic Acid - chemistry
Aspergillus niger - enzymology
Deglycosylation
Enzyme Activation
Enzyme Stability
Glucan 1,4-alpha-Glucosidase - chemistry
Glucan 1,4-alpha-Glucosidase - metabolism
Glucoamylase
Glycosylation
Hydrophobic and Hydrophilic Interactions
Irreversible thermoinactivation
Kinetics
Mannose - chemistry
Mannose - metabolism
Refolding
Structure-Activity Relationship
Subtilisin - metabolism
Temperature
Trehalose - chemistry
Trehalose - metabolism
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:A comparative structure–function study was performed to establish possible roles of carbohydrates in stabilization of glycoproteins, using glucoamylase (GA) as a model system. In addition to kinetic properties, stability toward elevated temperatures, extremes of pH, high salt concentrations together with circular dichroism, intrinsic/extrinsic fluorescence studies, proteolysis and affinity for interaction with hydrophobic ligands were investigated. Related to all the main properties examined, with one exception, glycosylation provided improvement in functional characteristics of the enzyme, especially in relation to its thermostability. Results are explained in terms of provision of stabilizing intermolecular interactions by the sugar molecules. The improvement in protein rigidity together with reduction of surface hydrophobicity appear to be especially important in relation to prevention of aggregation, an important mechanism of irreversible thermoinactivation, occurring at elevated temperatures.
ISSN:1570-9639
0006-3002
1878-1454
DOI:10.1016/j.bbapap.2005.03.011