Thermodynamic parameters for the binding of ATP by protonated open-chain polyamines

Abstract

The thermodynamic parameters of formation of ATP–protonated polyamine (ethylenediamine, 1,3-diaminopropane, putrescine, cadaverine, diethylenetriamine, spermidine, triethylenetetramine, spermine, tetraethylenepentamine and pentaethylenehexamine) complexes at 25 °C have been studied by potentiometry (H⁺-glass electrode and direct calorimetry). The formation constants of species for two, as yet untested, systems are also included. The thermodynamic parameters were obtained for all the systems studied from log K and ΔH⁰ values. It was found that ATP-protonated amine complexes are stabilized entropically. Empirical charge–stability relationships are shown