It is well known, and accepted, that it is essential to have “high quality” protein at the outset of a target based, small molecule drug discovery campaign. But what does “high quality” mean?
Certainly biological activity is a must. A high degree of purity (typically ≥95%) is another crucial requirement. Most often “purity” is defined based on the presence of other proteins in the preparation, but the presence of small molecules, whether or not of biological origin, also needs to be considered. However, the aggregation state is only rarely considered, and yet it significantly impacts…