3.4.7. HSA Esterase Activity (E.A.) Assay

The influence of QTP on the esterase activity of HSA was investigated by estimating the formation of p-nitrophenol [40]. The E.A. analysis is based on the fact that 4-nitrophenyl acetate (P-NPA) interacts with HSA and generates 4-nitrophenol (maximum absorption at 400 nm) [49,50]. For this experiment, the concentration of P-NPA (5 µM) and HSA (5 µM) was fixed, and the concentration of QTP increased (0–75 µM).
