The bioinorganic chemistry of zinc: synthetic analogues of zinc enzymes that feature tripodal ligands

Zinc, as a constituent of more than 300 enzymes, plays essential roles in b iological systems. The active sites of these enzymes feature a zinc center attached to the protein backbone by three or four amino acid residues, the nature of which influences the specific function of the enzyme. In order to understand why different zinc enzymes utilize different amino acid residue s at the active site, it is necessary to understand how, and why, the chemi stry of zinc is modulated by its coordination environment. Answers to these questions are being provided by a study of synthetic analogues of zinc enz ymes, i.e. small molecules that resemble the enzyme active sites. This arti cle provides an account of those studies that have specifically used tripod al ligands to mimic the active site protein residues in an effort to ascert ain the bioinorganic chemistry of zinc.