qm study on complexation profile between cyanide as an anionic inhibitor and active site of α-ca enzyme

density functional theory (dft) using b3lyp functional and split-valance 6-311g** basis set have been used to optimized the geometry of cyaide inhibitor and complex between this inhibitor with active site of α-carbonic anhydrase (ca) enzyme. according to calculated results the zinc cation in the active site of the ca enzyme prefers tetrahedral geometry. while the cyanide anion is coordinated to the zinc, the geometry could be change to trigonal bipyramidal or the tetrahedral geometry. also the cyanide anion belongs the second group of inhibitors of α-carbonic anhydrase which possess pharmacological applications.