Biophysical insight into the binding of triprolidine hydrochloride to human serum albumin: Calorimetric, spectroscopy and molecular docking approaches

Triprolidine hydrochloride is extensively used as antihistamine and anticholinergic drug. We have examine the binding mechanism of triprolidine hydrochloride (TRP) with human serum albumin (HSA) using fluorescence spectroscopy, circular dichroism (CD), isothermal titration calorimetry (ITC) and molecular docking techniques. The fluorescence data demonstrated that TRP binds to HSA through static quenching. The thermodynamic parameters (∆ H, ∆ S and ∆ G), binding stoichiometry and the binding constant between TRP and HSA were determined using ITC. Protein surface hydrophobicity of HSA has been calculated in presence and absence of TRP. CD results suggest the possibility of variation in the conformation of HSA in the presence of TRP. The binding site I was confirmed by molecular docking technique. The esterase-like activity of HSA shows that Arg-410 and Tyr-411 of sub-domain IIIA were directly involved in the binding process. Chemical unfolding study of HSA was carried out in the presence of TRP using GuHCl by CD and fluorescence spectroscopy.