title: Chemical and thermal stability of ferulic acid esterase-III from Aspergillus niger.
abstract: The stability of ferulic acid esterase III (FAE-III) from Aspergillus niger was examined using chemical and thermal denaturation. Thermal denaturation was irreversible and the loss of activity was dependent on pH. At 60 degrees C and pH 6.0, the rate constant of unfolding was 0.76 10(-3)/s, and the change in free energy of irreversible inactivation, deltaG*, was 101.9 kJ/mol. Sinapic acid, a product of the reaction of methyl sinapate with FAE-III, reduced the rate of unfolding (0.66 10(-3)/s at 0.1 mM sinapic acid). Chemical denaturation was performed using guanidine hydrochloride. FAE-III was very sensitive to this denaturant, and the midpoint of unfolding was 1.38 M guanidine hydrochloride at 30 degrees C, pH 6.0. The stability of FAE-III is compared to other enzymes.
authors.affiliation: Department of Biochemistry, Institute of Food Research, Norwich Research Park, Colney, UK.
authors.forename: G
authors.initials: G
authors.lastname: Williamson
authors.forename: J
authors.initials: J
authors.lastname: Vallejo
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology*; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism*; D004789:Enzyme Activation; D004795:Enzyme Stability; D019791:Guanidine / Q000737:chemistry / Q000494:pharmacology; D017510:Protein Folding; D013696:Temperature; D043325:Xylan Endo-1,3-beta-Xylosidase; D014995:Xylosidases / Q000737:chemistry / Q000378:metabolism
chemical_list: D002265:Carboxylic Ester Hydrolases; C070196:feruloyl esterase; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase; D019791:Guanidine