Osmolyte protection against urea denaturation of chymotrypsin

The destabilizing effect of urea on proteins can be counteracted by methylamines (osmolytes), such as trimethylamine N-oxide (TMAO), betaine, and sarcosine. This study compared the counteracting effects of these methylamines on urea-induced denaturation of α-chymotrypsin (CT). They measured the hydrodynamic diameter (dH) and the thermodynamic properties (Tm, ΔH, ΔGU, and ΔCp) with dynamic light scattering (DLS) and differential scanning calorimeter (DSC), respectively. The osmolytes strongly counteracted the urea actions on α-chymotrypsin, with TMAO having the strongest effect.

Venkatesu et al (2009). "Osmolyte Counteracts Urea-Induced Denaturation of alpha-Chymotrypsin." The Journal of Physical Chemistry B 113(15): 5327-5338.