title: A product inhibition study on adenosine deaminase by spectroscopy and calorimetry.
abstract: Kinetic and thermodynamic studies have been made on the effect of the inosine product on the activity of adenosine deaminase in a 50 mM sodium phosphate buffer, pH 7.5, at 27 degrees C using UV spectrophotometry and isothermal titration calorimetry (ITC). A competitive inhibition was observed for inosine as a product of the enzymatic reaction. A graphical-fitting method was used for determination of the binding constant and enthalpy of inhibitor binding by using isothermal titration microcalorimetry data. The dissociation-binding constant is equal to 140 microM by the microcalorimetry method, which agrees well with the value of 143 microM for the inhibition constant that was obtained from the spectroscopy method
authors.affiliation: Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran. saboury@chamran.ut.ac.ir
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Saboury
authors.forename: Adeleh
authors.initials: A
authors.lastname: Divsalar
authors.forename: Ghasem Ataie
authors.initials: GA
authors.lastname: Jafari
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Moosavi-Movahedi
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Housaindokht
authors.forename: Gholam Hosain
authors.initials: GH
authors.lastname: Hakimelahi
mesh_terms: D000241:Adenosine / Q000494:pharmacology; D000243:Adenosine Deaminase / Q000378:metabolism; D058892:Adenosine Deaminase Inhibitors; D000818:Animals; D001667:Binding, Competitive; D002152:Calorimetry, Differential Scanning; D002417:Cattle; D019277:Entropy; D006358:Hot Temperature; D007288:Inosine / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000201:enzymology*; D007700:Kinetics; D013056:Spectrophotometry, Ultraviolet; D013379:Substrate Specificity; D013816:Thermodynamics
chemical_list: D058892:Adenosine Deaminase Inhibitors; D007288:Inosine; D000243:Adenosine Deaminase; D000241:Adenosine