title: Arrhenius analysis of the electrophorus electricus acetylcholinesterase-catalyzed hydrolysis of acetylthiocholine.
abstract: Ellman's method was used to determine the Michaelis-Menten parameters for the hydrolysis of acetylthiocholine by Electrophorus electricus acetylcholinesterase from 12 to 37 degrees C. Arrhenius analysis revealed that the activation energy for formation of the enzyme/substrate complex is 22.2 +/- 1.1 kJ/mole. The Arrhenius plot of k(cat) is markedly curved and attributed to comparable rates of acylation and deacylation due to the absence of evidence for a temperature-dependent enzyme conformational change by differential scanning calorimetry.
authors.affiliation: Department of Chemistry and Physics, Texas Woman's University, Denton, TX 76201, USA.
authors.forename: Jesse
authors.initials: J
authors.lastname: Oakes
authors.forename: Tina
authors.initials: T
authors.lastname: Nguyen
authors.forename: B Mark
authors.initials: BM
authors.lastname: Britt
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism*; D000122:Acetylthiocholine / Q000378:metabolism*; D000215:Acylation; D000818:Animals; D002152:Calorimetry, Differential Scanning; D002384:Catalysis; D004557:Electric Organ / Q000201:enzymology*; D004593:Electrophorus / Q000378:metabolism; D006868:Hydrolysis; D007700:Kinetics; D011487:Protein Conformation; D013696:Temperature
chemical_list: D000122:Acetylthiocholine; D000110:Acetylcholinesterase