title: Effect of aniline coupling on kinetic and thermodynamic properties of Fusarium solani glucoamylase.
abstract: Purified glucoamylase (GA) from Fusarium solani was chemically modified by cross-linking with aniline hydrochloride in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) for 1 [aniline-coupled glucoamylase-1 (ACG-1)], 7 (ACG-7), and 13 min (ACG-13). The aniline coupling of GA had a profound enhancing effect on temperature, pH optima, and pK (a)'s of active site residues. The specificity constants (K (cat)/K (m)) of native, ACG-1, ACG-7, and ACG-13 were 136, 244, 262, and 208 at 55 degrees C for starch, respectively. The enthalpy of activation (DeltaH*) and free energy of activation (DeltaG*) for soluble starch hydrolysis were lower for the chemically modified forms compared to native GA. Proteolysis of ACGs by alpha-chymotrypsin and subtilisin resulted in activation.
authors.affiliation: Department of Chemistry, University of Agriculture, Faisalabad, 38040, Pakistan. hnbhatti2005@yahoo.com
authors.forename: Haq Nawaz
authors.initials: HN
authors.lastname: Bhatti
authors.forename: M Hamid
authors.initials: MH
authors.lastname: Rashid
authors.forename: Rakhshanda
authors.initials: R
authors.lastname: Nawaz
authors.forename: A Mukhtar
authors.initials: AM
authors.lastname: Khalid
authors.forename: Muhammad
authors.initials: M
authors.lastname: Asgher
authors.forename: A
authors.initials: A
authors.lastname: Jabbar
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry / Q000378:metabolism*; D005670:Fusarium / Q000201:enzymology*; D005087:Glucan 1,4-alpha-Glucosidase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D010447:Peptide Hydrolases / Q000378:metabolism; D013213:Starch / Q000378:metabolism; D013696:Temperature; D013816:Thermodynamics
chemical_list: D000814:Aniline Compounds; D013213:Starch; D005087:Glucan 1,4-alpha-Glucosidase; D010447:Peptide Hydrolases; C023650:aniline