A product inhibition study on adenosine deaminase by spectroscopy and calorimetry.
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
Saboury
Ali Akbar
AA
Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran. saboury@chamran.ut.ac.ir
Divsalar
Adeleh
A
Jafari
Ghasem Ataie
GA
Moosavi-Movahedi
Ali Akbar
AA
Housaindokht
Mohammad Reza
MR
Hakimelahi
Gholam Hosain
GH
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
D058892:Adenosine Deaminase Inhibitors; D007288:Inosine; D000243:Adenosine Deaminase; D000241:Adenosine