Spectroscopic Investigation of Procaine Interaction with Human Serum Albumin

Abstract

The interaction of Human Serum Albumin (HSA) with local anaesthetic, procaine hydrochloride is an important study from the viewpoint of pharmaceutical sciences to clarify the structure, function, and properties of HSA-drug complexes. The investigation has been carried through UV-absorption, Fluorescence and FTIR spectroscopy. The secondary structure of the protein and the binding mechanisms of the drug have been studied using Fourier self-deconvolution techniques on the obtained IR spectra. Analysis of UV-absorbance and fluorescence spectra of procaine-HSA complexes showed a weak binding ability in quenching the intrinsic fluorescence of HSA by combinations of static and dynamic quenching procedures. The binding constant (k) is calculated by graphical analysis and found to be in the range of (1.115-1.156) × 103 M-1 at 293 K. Spectral analysis of HSA-procaine compound has revealed a relative decrease in the intensity of the absorption band of α helix relative to that of β-sheets. This change in intensity is mainly due to the formation of Hbonding in procaine-HSA complex. Keywords: Procaine; HSA; Binding constant; Protein secondary structure; FT-IR spectroscopy