Redox in Biological Systems

We are currently interested in oxidation and reduction (redox) reactions in biological systems. In particular, we are studying the reactions of the tripeptide g-glutamyl cysteinyl glycine (glutathione). Glutathione is a major cellular antioxidant in most biological systems. It can exist in a reduced thiol form (GSH) and an oxidized disulfide form (GSSG). Glutathione is the major non-protein thiol in most plants and animals, and part of its function is as a cellular redox buffer, maintaining biological molecules in the correct redox state. GSH also plays a role in the protection of molecules and cells from damaging reactive oxygen species. We are developing methods for the separation of GSH and GSSG, and the determination of their individual concentrations.

Glutathione reductase (GR) is the enzyme which maintains glutathione in its reduced form. The enzyme contains a bound Flavin (FAD) and a redox active disulfide at its active site, and also requires NADPH as a co-factor.

We are interested in comparing the structure, stability, and activity of glutathione reductase from different sources and in different isoforms. We are also studying naturally occurring inhibitors and protectors of glutathione reductase.

Students will use UV-Visible spectroscopy, High Performance Liquid Chromatography (HPLC), Fast Protein Liquid Chromatography (FPLC), Electrospray Ionization Mass Spectrometry (ESI-MS), centrifugation, and ultrafiltration during the course of these studies.

Additional Information

James Swan
Associate Professor
Department of Chemistry,
Bucknell University

e-mail: swan@bucknell.edu
phone: 570-577-3671
fax: 570-577-1739