A Comprehensive Insight into Binding of Hippuric Acid to Human Serum Albumin: A Study to Uncover Its Impaired Elimination through Hemodialysis

Abstract

Binding of hippuric acid (HA), a uremic toxin, with human serum albumin (HSA) has been examined by isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), molecular docking, circular dichroism (CD) and fluorescence spectroscopy to understand the reason that govern its impaired elimination through hemodialysis. ITC results shows that the HA binds with HSA at high (K b ∼104) and low affinity (K b ∼103) sites whereas spectroscopic results predict binding at a single site (K b∼103). The HA form complex with HSA that involves electrostatic, hydrogen and hydrophobic binding forces as illustrated by calculated thermodynamic parameters. Molecular docking and displacement studies collectively revealed that HA bound to both site I and site II; however, relatively strongly to the later. Esterase-like activity of HSA confirms the involvement of Arg410 and Tyr411 of Sudlow site II in binding of HA. CD results show slight conformational changes occurs in the protein upon ligation that may be responsible for the discrepancy in van’t Hoff and calorimetric enthalpy change. Furthermore, an increase in and is observed from DSC results that indicate increase in stability of HSA upon binding to HA. The combined results provide that HA binds to HSA and thus its elimination is hindered.

Study of the Interaction of Ciprofloxacin and Sparfloxacin with Biomolecules by Spectral, Electrochemical and Molecular Docking Methods

“…Since both drugs has an extended aromatic part and functional groups suitable for hydrogen bonding, it can be expected that this phenolic type molecule is able to interact strongly with biomolecules and that these non-covalent interactions may play a decisive role in its mechanism of action. Both drugs used to treat community-acquired lower respiratory tract infections (acute sinusitis, exacerbations of chronic bronchitis caused by susceptible bacteria, and community-acquired pneumonia) [12]. Because of its pharmacological activity, the investigation of the interactions between this compound and biomolecules are very important [13].…”

“…Because of its pharmacological activity, the investigation of the interactions between this compound and biomolecules are very important [13]. Furthermore, binding of drugs to albumin alters the pattern and volume of distribution, lowers the rate of clearance, and increases the plasma half-life of the drug [12][13][14][15].…”

“…It binds and transport a large variety of ligands including hormones, fatty acids, drugs, etc. [10][11][12]. It is a globular, multifunctional protein composed of three structurally similar domains each containing two subdomains and having molecular weight of 67 kD stabilized by 17 disulfide bonds [13].…”

Interaction of human serum albumin with uremic toxins: a thermodynamic study

“…Thus, calorimetric and spectroscopic methods have proven to be very suitable to characterized binding thermodynamics of ligands to proteins, namely ITC 10,12,13,[22][23][24][25] and uorescence spectroscopy. 10,12,13,[23][24][25] Other groups characterized binding isotherms by equilibrium dialysis (ED), 3,4,13,26,27 capillary electrophoresis (CE) [28][29][30] and chromatographic techniques.…”

“…4,5,9 Most toxins are found to interact with either one or both of the hydrophobic binding sites Sudlow I and II of HSA located in the subdomains IIA and IIIA. [10][11][12][13] Due to their tight binding, these small protein-bound and hydrophobic molecules are poorly cleared during conventional dialysis.…”