There are many different small molecules that can function to enhance protein stability and folding, many of them can be broadly grouped into large classes based both on their structure and their proposed mechanism of action. The parameters that define these groups are not strictly defined, and many small molecules that exert a chemical chaperoning effect do not readily fall into one of these categories. For example, the free amino acid arginine is not classically defined as a chemical chaperone, but it has a well-documented anti-aggregation effect.[1]