The effect of protein stability on protein–monoglyceride interactions

Abstract

We have previously shown that proteins such as β-lactoglobulin and lysozyme insert into monoglyceride monolayers and are able to induce an L β to coagel phase transition in monoglyceride bilayers. These studies gave a first indication that protein stability could be an important factor for these interactions. This study therefore aims at further investigating the potential role of protein stability on protein–monoglyceride interactions. To this end we studied the interaction of stable and destabilized α-lactalbumin with monostearoylglycerol. Our results show that protein stability is important for the insertion of proteins into a monostearoylglycerol monolayer, such that the lower the stability of the protein the better the protein inserts. In marked contrast to β-lactoglobulin and lysozyme we found that destabilized α-lactalbumin does not induce the L β to coagel phase transition in monoglyceride bilayers. We propose that this is due to an increased surface coverage by the protein which could result from the unfolding of the protein upon binding to the interface.