Fig. 6

Binding affinity between CSP and α-pinene by competitive binding assay. a SDS-PAGE of the purified protein of CSP; M: molecular weight marker of 15, 25, 35, and 40 kDa. b Binding of 1-NPN to CSP. 4 μM of protein in Tris buffer was used here. And aliquots of a 1 mM methanol solution of 1-NPN were added to the protein to final concentrations of 2, 4, 6, 8, 10 12, 14, 16, 18 and 20 μM (indicated as black, blue, red, dark blue, grey, light green, dark green, yellow and purple, respectively), and the emission spectra were recorded. c The binding curve and the relative Scatchard plot of binding. d Competitive binding of α-pinene to CSP. Protein (4 μM) was incubated with 1-NPN (4 μM) and aliquots of different concentrations of ligand were added. For each set of data, fluorescence values were plotted as percent of that obtained in the absence of competitor