Spectroscopic investigation of copper(II) bovine carbonic anhydrase and its inhibitor derivatives

Abstract

Cooper(II) bovine carbonic anhydrase and its derivatives with ligands which act as inhibitors of the native zinc(II) and of the cobalt(II) enzyme have been investigated by n.m.r. and e.s.r. spectroscopy. Measurements of T₁ of the water protons of copper enzyme solutions have shown that in the donor set there is a group containing mobile hydrogens which is not substituted by anionic donors. The derivatives with anionic ligands have been assigned a five-co-ordinate structure, whereas the sulphonamide derivatives have been assigned a pseudo-tetrahedral stereo-chemistry. For the copper enzyme a five-co-ordinate structure is also suggested, in which the distance between the metal atom and one of the donors is longer than normal.