HSA-NEP is a fusion protein with potential uses in treating Alzheimers disease. It consists of Neprilysin, a peptide degrading enzyme, linked to HSA, the most common protein in blood plasma. Fusion proteins such as HSA-NEP are often stored in glass (silica) containers, to which they adsorb, often causing denaturation of the protein. We have investigated dynamic adsorption of HSA-NEP to the silica-water interface using spectroscopic ellipsometry and FTIR to determine the adsorbed amount and secondary structure changes, but this does not give a true physical structural picture of the protein adsorbed. Dynamic neutron reflection measurements will be unique to unravel how interfacial structure of HSA-NEP changes as a function of time, pH and concentration. As the pIs for HSA and NEP are different, it is interesting to explore how they change in the adsorbed layer with pH.
