title: Stabilizing effect of various polyols on the native and the denatured states of glucoamylase.
abstract: Different spectral probes were employed to study the stabilizing effect of various polyols, such as, ethylene glycol (EG), glycerol (GLY), glucose (GLC) and trehalose (TRE) on the native (N), the acid-denatured (AD) and the thermal-denatured (TD) states of Aspergillus niger glucoamylase (GA). Polyols induced both secondary and tertiary structural changes in the AD state of enzyme as reflected from altered circular dichroism (CD), tryptophan (Trp), and 1-anilinonaphthalene-8-sulfonic acid (ANS) fluorescence characteristics. Thermodynamic analysis of the thermal denaturation curve of native GA suggested significant increase in enzyme stability in the presence of GLC, TRE, and GLY (in decreasing order) while EG destabilized it. Furthermore, CD and fluorescence characteristics of the TD state at 71°C in the presence of polyols showed greater effectiveness of both GLC and TRE in inducing native-like secondary and tertiary structures compared to GLY and EG.
authors.affiliation: Biomolecular Research Group, Biochemistry Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Mohammed Suleiman
authors.initials: MS
authors.lastname: Zaroog
authors.forename: Habsah
authors.initials: H
authors.lastname: Abdul Kadir
authors.forename: Saad
authors.initials: S
authors.lastname: Tayyab
mesh_terms: D002942:Circular Dichroism; D004795:Enzyme Stability / Q000187:drug effects; D019855:Ethylene Glycol / Q000494:pharmacology; D005087:Glucan 1,4-alpha-Glucosidase / Q000737:chemistry*; D005990:Glycerol / Q000494:pharmacology; D011108:Polymers / Q000494:pharmacology*; D017510:Protein Folding / Q000187:drug effects; D014199:Trehalose / Q000494:pharmacology
chemical_list: D011108:Polymers; C024617:polyol; D014199:Trehalose; D005087:Glucan 1,4-alpha-Glucosidase; D019855:Ethylene Glycol; D005990:Glycerol