With this award, the Chemistry of Life Processes Program in the Chemistry Division is funding Dr. Chin-Chuan Wei from Southern Illinois University Edwardsville who is investigating an important class of proteins that have been implicated in disease processes such as atherosclerosis and tumor growth. The program involves studying how the functions of these proteins are ultimately related to their unique structures as governed by weak interactions between various proteins and other molecules. The Professor Wei is characterizing these weak interactions in an effort to understand the similarities and differences of these protein functions and to provide new insights in enzymology. The project participants, including undergraduate and M.S. graduate students, acquire specialized training in protein preparation and characterization techniques, that enhance fundamental research programs at a primary undergraduate institution. The project also recruits underrepresented students and high school students to biochemical research. <br/><br/>This research project uses biophysical techniques to elucidate the enzymatic mechanism of two related enzymes, NADPH oxidase 5 and dual oxidase. Their enzymatic activities are modulated by several factors including domain-domain and protein-protein interactions. These interactions are investigated by ultra-sensitive calorimetry and UV/fluorescence spectroscopy to obtain thermodynamic and kinetic parameters, as well as information about structural changes. In addition, the dissimilarities between their sequences, phosphorylation, and auxiliary protein recognition sites are investigated for their distinct activity profiles. Information from this study provides a molecular understanding of these two enzymes in regards to their catalysis and regulation, defining a new model system for exploring non-phagocyte NADPH Oxidases.