Oil/alkanethiol layers for the study of emulsified protein conformation bysurface plasmon resonance using monoclonal antibodies

A method combining surface plasmon resonance and epitope mapping was develo ped to study the protein conformation at the oil/ water interface of an emu lsion. The conformation of beta-lactoglobulin stabilizing dodecane/water an d miglyol/water interfaces was investigated using five anti-beta-lactoglobu lin monoclonal antibodies. The developed method allows us to specifically r ecognize the emulsified beta-lactoglobulin at the surface of a sensor chip with good repeatability; i.e., standard deviations range between 0.7 and 3. 6%. Considering that the monoclonal antibodies, recognizing conformational epitopes, still bind to beta-lactoglobulin at oil/water interfaces, it is c oncluded that the protein retains a globular conformation. It is shown that the inhibition-binding values of two pairs of Mabs are different for beta- lactoglobulin stabilizing dodecane/water and miglyol/water interfaces. This indicates that the conformations of emulsified beta-lactoglobulin are slig htly different according to the nature of the oil phase. (C) 2000 Academic Press.