Reaction of the Anticancer Organometallic Ruthenium Compound (η6-p-Cymene)Ru(ATSC)ClPF6 with Human Serum Albumin

摘要

The reaction of [(η⁶-p-cymene)Ru(ATSC)Cl]PF6 (ATSC = 9-anthraldehyde thiosemicarbazone) with human serum albumin was investigated at different temperatures using fluorescence and infrared spectrophotometry. The binding constant, K, for the reaction was determined using a number of different methods. Using a modified Stern-Volmer equation, K was determined to be 9.09 × 10⁴, 12.1 × 10⁴, and 13.1 × 10⁴ M⁻¹ at 293 K, 298 K, and 308 K, respectively. A thermodynamic analysis showed that the reaction is spontaneous with ΔG being negative. The enthalpy of reaction ΔH = 16.5kJ mol⁻¹ and the entropy of reaction ΔS = 152 Jmol⁻¹K⁻¹. The values of ΔH and ΔS suggest that hydrophobic forces are dominant in the mode of interaction and that the process is mostly entropy driven.