Spinodal surface of a free energy model for eyelens protein mixtures: Relevance for cataracts

摘要

We studied the phase behavior of a model binary mixture of eye lens crystallin proteinsusing first-order thermodynamic perturbation theory. The instability boundary, or spinodal surface,was found to be very sensitive to the strength of the attraction between the two proteins, and also torespond to this interprotein attraction strength in a non-monotonic fashion. In particular, in the caseof either weak or strong attractions, these eye lens solutions become thermodynamically unstable.Interestingly, attraction strengths that correspond closely to those of proteins isolated from the livinglens fall right within the stable region of the phase diagram. This non-monotonic stability suggestsnew molecular mechanisms for eye lens opacification in cataract.