Ethylammonium nitrate (EAN) is a liquid organic salt that has many potentia
l applications in protein chemistry. Because this solvent has hydrophobic a
nd ionic character as well as the ability to hydrogen bond, it is especiall
y well suited for broad use in protein crystallography. For example, EAN ma
y be used as an additive, a detergent, a precipitating agent or to deliver
ligands into protein crystals. A discussion of the crystallization of lysoz
yme using EAN as a precipitating agent is given here.