Binding properties of adenosine deaminase interacted with theophylline.
Thermodynamic studies were carried out to evaluate the binding of theophylline on adenosine deaminase (ADA) in 50 mM sodium phosphate buffer pH 7.5, at 300 K, using isothermal titration calorimetry (ITC). A simple method for determination of binding isotherm in the drug--ADA interaction was applied using ITC data. ADA has two binding sites for theophylline, which show positive cooperativity in its sites. The intrinsic association equilibrium constants are 6 and 52 mM(-1) in the first and second binding sites, respectively. Hence, occupation of the first site has produced an appreciable enhancement by 8.7 of the binding affinity of the second site. The molar enthalpies of binding are -12.2 and -14.9 kJ/mol in the first and second binding sites, respectively.
Saboury
Ali Akbar
AA
Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran. saboury@chamran.ut.ac.ir
Bagheri
Soghra
S
Ataie
Ghasem
G
Amanlou
Masoud
M
Moosavi-Movahedi
Ali Akbar
AA
Hakimelahi
Gholam Hossein
GH
Cristalli
Gloria
G
Namaki
Saeid
S
D000243:Adenosine Deaminase / Q000737:chemistry*; D001993:Bronchodilator Agents / Q000737:chemistry*; D002151:Calorimetry; D008024:Ligands; D010726:Phosphodiesterase Inhibitors / Q000737:chemistry*; D011485:Protein Binding; D013806:Theophylline / Q000737:chemistry*; D013816:Thermodynamics; D017186:Titrimetry
D001993:Bronchodilator Agents; D008024:Ligands; D010726:Phosphodiesterase Inhibitors; D013806:Theophylline; D000243:Adenosine Deaminase