Protein crystallization is of great interest due to its crucial role for the determination of protein structures, as well as in other fields such as drug engineering by pharmaceutical industries [J. Gunton et al. Protein Condensation: Kinetic Pathways to Crystallization and Disease. CUP, (2007)]. Despite its importance, a fundamental understanding of the mechanisms underlying such a process is still missing. Recently, both experimental [F. Zhang et al. Journal of Applied Crystallography 44, (2011)] and theoretical [P. G. Vekilov, Nanoscale 2, (2010)] studies have shown that, under certain conditions, crystallization follows a two-step mechanism, rather than the classical nucleation pathway. In order to gain a better understanding of such processes, an in situ study of the dynamics of two suitable crystallizing systems by QENS at IN16B may provide new extremely useful information, thus potentially significantly improving the general physical picture.