Enzyme Catalysis

The mechanisms of cofactor dependent enzymes are a major focus of our research. We have particular interest in flavoprotein and quinoprotein systems and more recently other cofactors including haem, cobalamin and metal centres. These cofactor systems are a rich source of spectroscopic information making them ideal for detailed analysis using fast reaction kinetics and related methods. A unifying aspect of our work is an understanding of the role of dynamics in coupling to enzyme reaction coordinates, and development of experimental and theoretical methods to access dynamics across multiple timescales (femtoseconds to seconds). The challenge is to map spatially and temporally dynamical changes that are associated with the enzyme chemistry and to quantify the effects of dynamic contributions to turnover and catalysis.

Much of our research focuses on the mechanisms of electron and hydrogen transfer, with particular emphasis on flavoprotein and quinoprotein enzymes. We are studying the dynamics of weakly assembling electron transfer complexes, and how dynamical processes facilitate electron transfer between partner proteins. Our work involves studies of electron and hydrogen transfer in bacterial and mammalian proteins, including nitric oxide synthase, methionine synthase/reductase, cytochrome P450 reductases, monoamine and related amine oxidases. Understanding fundamental mechanisms of electron and hydrogen transfer has major biomedical implications for example cardiovascular disease, developmental abnormalities, drug metabolism and therapeutic intervention. We are also developing new approaches to studying 'tunnelling' reactions in biology through the use of biophysical and chemical methods (e.g. pressure, cryogenics, isotope effects). We have established programmes on small molecule inhibition of selected enzymes, for example those involved in the kynurenine pathway which is a target for neurodegenerative diseases such as Huntington's, Parkinson's and Alzheimer's diseases.

Some Recent Enzyme Catalysis Publications: