Investigation of the behavior of alpha casein upon binding to fluvastatin and pitavastatin: A spectroscopic study and molecular modeling

The interaction between alpha casein (α-CN) and two drugs, fluvastatin (FLU) and pitavastatin (PIT) was investigated using fluorescence, UV absorption and FTIR. In addition, the binding site was established by applying molecular modeling technique. Fluorescence data suggested that FLU and PIT quench the intrinsic fluorescence of α-CN. The binding constants for the interaction of FLU and PIT with α-CN were found to be (8.18±0.08)×104 M-1 and (9.04±0.07)×104 M-1, respectively, indicating that the binding affinity of PIT to α-CN was higher than that for FLU. The number of binding site FLU and PIT per α-CN were 1.06 and 1.04 respectively. Docking calculation showed the probable binding sites of FLU and PIT are located in the hydrophobic core of α-CN where the FLU and PIT are lined by hydrophobic residues and make three and four hydrogen bonds with FLU and PIT respectively. Simulation, molecular docking and experimental data reciprocally supported each other. Therefore, it can be concluded that α-CN can act as a carrier of FLU and PIT drugs.