Spectroscopic and thermodynamic interaction of anti-diabetic drug with globular proteins

K. M. Sachin¹, Sameer A. Karpe¹, Man Singh¹, Ajaya Bhattarai¹,²*

¹School of Chemical Sciences, Central University of Gujarat, Gandhinagar, India

²Department of Chemistry, M.M. A. M. Campus, Tribhuvan University, Biratnagar, Nepal

*Corresponding author: bkajaya@yahoo.com

ABSTRACT

Background: The drug-protein interaction is a fundamental problem in estimating the serious side effects of the drug. Objective: This study aimed to  see the interaction of acarbose with three different globular proteins i.e. bovine serum albumin (BSA), human serum albumin (HSA), and hemoglobin (Hb) via UV-Visible absorption spectroscopic analysis. Materials and Methods: BSA, HSA and Hb stock solutions (10 μM) were prepared in 0.1M phosphate buffer (1X PBS) of pH 7.4. The acarbose concentrations were varied from 10-100 μM into 10 μM and used as a solute for 10 μM BSA, HSA, and Hb solution. All solutions were prepared at 298.15 K and atmospheric pressure (p = 0.1 MPa) using Milli-Q water of 0.71 μS∙cm^-1, at pH 7. All prepared solutions were stored in the dark at 4 °C. UV-vis absorption spectra were recorded.Using a statistical method of non-linear regression (NLREG), binding constant and distribution constant were determined. Also, thermodynamic parameters like activation energy, enthalpy, entropy and Gibbs free energy were determined by using UV-visible data. Results: The properties of acarbose-protein complexes indicated that the hydrogen bonding and weak van der Waals force played a major role in the interaction for complexation. Conclusion: The binding of acarbose with different proteins leads to change in the structure of protein folding which confirms by physicochemical and thermodynamic analysis.

Key words: Acarbose, Bovine serum albumin, Human Serum albumin, Hemoglobin