This award in the Inorganic, Bioinorganic, and Organometallic Chemistry program supports research by Dr. Alison Butler of the Chemistry Department, University of California at Santa Barbara, on marine haloperoxidase enzymes. The reactivities of vanadium bromoperoxidase and FeHeme bromoperoxidase, including their roles in biosynthesis, will be investigated using functional model complexes and enzyme studies. Vanadium complexes of alpha-helical peptides and alpha-helical peptide bundles that closely resemble vanadium haloperoxidases will be synthesized and tested. In addition some new mesoporous and titanium dioxide materials will be prepared and tested for peroxidative halogenation reactivity. Reactivity comparisons will be made to marine haloperoxides isolated from chiral halogenated acetogenins and sesquiterpenes produced from marine algae. The halide selectivity of vanadium haloperoxidases from algae that evolve chlorinated and brominated hydrocarbons will be investigated. Many marine natural products and enzymes have important industrial applications in the specialty chemical, diagnostics, pharmaceutical, and biotechnology industries. Development of the use of some of these natural products has been inhibited by lack of availability of sufficient quantities. This work will identify functional mimics for some marine haloperoxidases present in marine algae. These compounds have potential use as catalysts for production of oxidants and halogenating agents in situ, processes that would be environmentally beneficial alternatives to present technology.