Chelerythrine chloride binding of guanosine in aqueous solution

In this work, the interaction between chelerythrine (CHE) and guanosine is studied using UV-vis and fluorescence measurements at various temperatures. The UV-vis spectra show that the increasing guanosine concentrations result in the decreasing absorption intensity and red shift of CHE E absorption band (267 nm). The fluorescence spectra are fitted to linear analysis, yielding a binding constant of 1.04 x 10(4) L/mol at 298.15 K of CHE with guanosine. Besides, with Delta H-r(m)Theta = -8.26 kJ/mol, Delta(r)G(m)(Theta) = -22.90 kJ/mol, and Delta S-r(m)Theta = 49.38 J/(mol K) the interaction should be entropy-driven and exterothermic. (C) 2008 Xiong Hui Wei. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.