Sphingomyelin-induced structural modification of native human hemoglobin and its chemically and thermally disrupted secondary structure: A photophysical exploration

Binding mechanism and antioxidant activity of piperine to hemoglobin

Piperine (PIP) is the most active main component in pepper. The interaction of small molecules with biomolecules leads to structural and functional changes. In this study, the binding mechanism and antioxidant activity of PIP with hemoglobin (Hb) are presented using spectroscopic and computational methods. Results showed that the redox activity of PIP on Hb showed concentration dependence. Fluorescence and isothermal titration calorimetric experiments showed that the Hb-PIP system had a static quenching mechanism at a single binding site. The addition of PIP caused a slight perturbation to the secondary structure of Hb by structural analysis. The structural stability of the Hb-PIP binding system was demonstrated by molecular dynamics simulations, and molecular docking and thermodynamic constants confirmed that the electrostatic interaction force was dominant in the energy contribution of the system. Research results are conducive to the potential use of PIP in related meat products.