Potential application of arginine in interaction analysis

Aqueous solution of 0.1-2 M arginine at mildly acidic to neutral pH is widely used in biotechnology and protein research, including protein refolding, purification, and formulation. This is largely because of its ability to suppress non-specific protein-protein and protein-surface interactions. Here we propose potential applications of arginine in interaction analysis for proteins. One of the important goals of such analysis is discovery of small molecule antagonistic or agonistic ligands that bind to target proteins and thereby modulate their function. Such research is often hampered by the low solubility of the small molecules, the instability of target proteins and the non-specific protein-ligand interactions. Aqueous arginine solution increases the solubility of small molecules, which should give an alternative to conventional dissolution method of small molecules by organic solvents. Arginine may also directly impact on the analysis of protein-protein or protein-ligand interactions by suppressing weak non-specific interactions.