ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Effect of dielectric medium on angiotensin converting enzyme inhibitors binding to Zn²⁺

Martin Šramko, Július Šille, Pavol Ježko, and Vladimír Garaj

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Comenius University, Odbojarov 10, SK-831 04 Bratislava, Slovak Republic

E-mail: garajv@fpharm.uniba.sk

Received: 20 July 2009  Revised: 18 September 2009  Accepted: 21 September 2009

Abstract: The Becke3LYP density functional was used to study structural and thermodynamic parameters of bivalent zinc cation complexes with selected substrates and ACE inhibitors (H₂O/OH⁻, neutral forms of captopril, zofenoprilat, omapatrilat, CH₃CONHCH₃, and N-terminal anions of captopril, zofenoprilat, omapatrilat, enalaprilat, perindoprilat, trandolaprilat, and fosinoprilat). The combination of DFT and the conductor-like polarizable continuum model (CPCM) were employed to compute the Gibbs interaction energies (ΔG) between Zn²⁺ and the selected ACE inhibitors for dielectric media with ɛ = 5 (to simulate the protein environment) and for water media (ɛ = 78.39) for comparison purposes. The results show that ΔG is sensitive to the dielectric constant of the environment and that lower dielectric medium favors the binding of inhibitors to the zinc cation.

Keywords: ACE inhibitors - DFT - Interaction Gibbs energy - Zn(II) complexes - dielectric constant

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-010-0005-y

Chemical Papers 64 (3) 395–404 (2010)