The Abnormal Oswald Ripening of Protein Nanofiber in Myofibrillar Protein Solution

Abstract

In solutions of myofibrillar protein extracted from giant squid (Dosidicus gigas), the size-coarsening process of protein nanofiber is complex. At high temperature (25{degrees}C), nanofiber keeps growth but with two distinguishable patterns, slow rate at the initial stage with t0.2 and the fast one at the late stage with t2.3. The intersection of these two slopes is around 300 min. Meanwhile, protein concentration in solution enhances as well. These behaviors contradict to the prediction of Ostwald ripening. Thus, we call this process as abnormal. These abnormal behaviors come from the conformation change of some types of constitution protein molecules with chemical potential reduction when they dissolve from nanofiber to solution. On the other hand, low temperature (10{degrees}C) depresses this size growth. This observation suggests that temperature regulates protein molecule conformation change in nanofiber. The consequence of this abnormal Ostwald ripening process is that all protein molecules in nanofiber are redistributed. Protein molecules with the absence of conformation change in dissolution accumulate in nanofiber to cause it growing, while the rest concentrates in solution.