The present application involves a comprehensive investigation of the basic enzymological and spectroscopic properties of four related mononuclear molybdenum enzymes: xanthine oxidoreductase, sulfite oxidase, DMSO reductase and arsenite reductase. This group includes representatives of all three major families of mononuclear molybdenum enzymes. The overall goal of the proposed work is to gain a more complete understanding of fundamental aspects of the mechanism of action of each of these enzymes by comparing and contrasting their physical, chemical and electronic structures. A comparison among enzymes type with regard to the relationship of structure to function will also be made. To this end a series of rapid reaction kinetic, spectroscopic, theoretical and molecular biological studies will be undertaken that build directly on past work in the PI's laboratory. The proposed work is intended to integrate both mechanistic and spectroscopic studies of these enzymes with their known crystal structures and to elucidate underlying themes in reactivity by comparing and contrasting their properties. This approach that has proven extremely successful in studies of the generally much better understood biological systems that possess heme and flavin prosthetic groups.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
Project #
Application #
Study Section
Biochemistry Study Section (BIO)
Program Officer
Preusch, Peter C
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Ohio State University
Schools of Medicine
United States
Zip Code
Hemann, Craig; Hood, Brian L; Fulton, Meita et al. (2005) Spectroscopic and kinetic studies of Arabidopsis thaliana sulfite oxidase: nature of the redox-active orbital and electronic structure contributions to catalysis. J Am Chem Soc 127:16567-77
Hemann, Craig; Ilich, Predrag; Stockert, Amy L et al. (2005) Resonance Raman studies of xanthine oxidase: The reduced enzyme-product complex with violapterin. J Phys Chem B 109:3023-31
Leimkuhler, Silke; Stockert, Amy L; Igarashi, Kiyohiko et al. (2004) The role of active site glutamate residues in catalysis of Rhodobacter capsulatus xanthine dehydrogenase. J Biol Chem 279:40437-44
Hoke, Kevin R; Cobb, Nathan; Armstrong, Fraser A et al. (2004) Electrochemical studies of arsenite oxidase: an unusual example of a highly cooperative two-electron molybdenum center. Biochemistry 43:1667-74
Choi, Eun-Young; Stockert, Amy L; Leimkuhler, Silke et al. (2004) Studies on the mechanism of action of xanthine oxidase. J Inorg Biochem 98:841-8
Okamoto, Ken; Matsumoto, Koji; Hille, Russ et al. (2004) The crystal structure of xanthine oxidoreductase during catalysis: implications for reaction mechanism and enzyme inhibition. Proc Natl Acad Sci U S A 101:7931-6
Atreya, Chloe E; Johnson, Eric F; Irwin, John J et al. (2003) A molecular docking strategy identifies Eosin B as a non-active site inhibitor of protozoal bifunctional thymidylate synthase-dihydrofolate reductase. J Biol Chem 278:14092-100
Conrads, Thomas; Hemann, Craig; George, Graham N et al. (2002) The active site of arsenite oxidase from Alcaligenes faecalis. J Am Chem Soc 124:11276-7
Powers, Rachel A; Morandi, Federica; Shoichet, Brian K (2002) Structure-based discovery of a novel, noncovalent inhibitor of AmpC beta-lactamase. Structure 10:1013-23
Stockert, Amy L; Shinde, Sujata S; Anderson, Robert F et al. (2002) The reaction mechanism of xanthine oxidase: evidence for two-electron chemistry rather than sequential one-electron steps. J Am Chem Soc 124:14554-5

Showing the most recent 10 out of 17 publications