This paper describes the construction of a multicomponent film via layer-by-layer (LbL) method and the kinetic analysis of the interaction between horseradish peroxidase (HRP) enzyme on calf thymus double-stranded DNA layer on a modified gold surface. Surface plasmon resonance (SPR) and electrochemical impedance spectroscopy (EIS) are used to characterize the successful construction of the film on the gold surface. Surface plasmon resonance provided essential information for the study and characterization of protein and nucleic acid interaction and this method is label-free and monitors the interactions in real time. The kinetic studies determined by SPR of the horseradish peroxidase film formation on ds-DNA layer showed values of 24.7 L mol-1 s-1 and 1.2×10-3 s-1 for k a and k d, respectively. The Gibbs free energy obtained for the system was -23.1 kJ mol-1. The results obtained show that the interaction of the enzymes molecules on ds-DNA is kinetically and thermodynamically favourable and the interaction among the layers probably occurs mainly by attraction of opposite charges.
SPR; EIS; kinetic adsorption; DNA; HRP; protein-DNA interaction
