| The binding of 5-hydroxy-2-hydroxymethyl-4-pyrone (Kojic acid, KA) and 5-hydroxy-l-methyl-2hydroxymethylene-1H-pyridin-4-one (N-methyl kojic acid, N-KA) with environmentally relevant toxic metal ions (e.g Ag+, Al3+, As3+, Cd2+, Co 2+, Cr3+, Cu2+, Fe3+, Ga3+, Gd3+, Hg2+, In3+ , Pb2+) were characterized by isothermal titration calorimetry (ITC). The purpose of this study was two fold: (i) to investigate the thermodynamics of binding of the fungal metabolite, Kojic acid and its derivative, N-methyl-3-hydroxy-6-hydroxymethylpyridin-4-one to these environmentally relevant toxic metals and some other metals (In3+, Ga 3+ and Gd3+) that have applications in radiotherapy and imaging. These metals have been implicated in various disease conditions. (ii) Previous work has established the binding of Kojic acid and its derivatives to iron. We looked at the possibility of binding to these toxic metals. The underlying tenet is that such information will be invaluable for ligand design of the specific chelators for various toxic metals ions since thermodynamic data can be used to design and optimize drugs. From the data obtained, it can be noted that KA and N-KA formed complexes with all the metals titrated. The binding of all the metals to both substrates were enthalpically-driven. |
