The Factors Governing the Coordination Number in the Anion Derivatives of Carbonic Anhydrase

Abstract

The electronic and ¹H NMR spectra of cobalt(II)-substituted carbonic anhydrase in the presence of NCS⁻, N₃ ⁻ and NCO⁻ on one side and CH₃COO⁻, ClO₄ ⁻ and NO₃ ⁻ on the other are presented here and discussed in the light of the available X-ray data on two kinds of inhibitors. The aim of this article is to focus on the factors which determine the coordination number of the inhibitor derivatives. It is proposed that the hydrophobic or the hydrophilic character of the inhibitors provide an important contribution to the energy balance between four and five coordination.

Key Words:

• carbonic anhydrase
• ¹H NMR spectroscopy
• electronic spectroscopy
• anion binding to metalloenzymes
• cobalt-substitution in metalloenzymes