Reactions of isolated mono-molecular protein films

Abstract

Wash-out of the forming solution from mono-molecular casein films at the air–water interface is demonstrated and allows the perfusion of the subphase by inorganic and protein solutions. In this way, using X-ray reflectometry, we have observed the effects of calcium binding to β-casein films and the inter-protein association of β-casein and κ-casein in an order-specific manner. The method is of general utility for monolayer reactions and here the relevance to self-assembly of the casein micelle is discussed.