Protein-surfactant interactions at an interface play an important role for broad applications in the chemical, dairy, cosmetic and pharmaceutical industries. Rubisco is the most abundant protein in nature, and sodium dodecyl benzyl sulphonate (SDOBS) is one of the most important synthetic surfactants in detergents and cleaning agents. In this work we will investigate the interaction of Rubisco with SDOBS at the air-water interface by neutron reflection. Contrast variation will be obtained by combined measurement in null water using deuterated and protonated SDOBS, giving the surface excess of Rubisco and SDOBS independently. This project will provide insights on the interaction of proteins and surfactants at the interface, and elucidate the mechanism by which SDOBS disassembles an interfacial Rubisco protein network