The production of high quality protein samples is crucial in obtaining meaningful biophysical data. In contrast to nucleic acids, proteins do not share an appreciable number of common traits, which makes the production and purification of active and well defined samples of the protein of interest quite challenging and unique: One-size-fits-all strategies are seductive but often lead to failure. Knowledge about the overall purity of the protein sample, as estimated by for example SDS-PAGE gel analysis, is by far not sufficient. The best possible starting point for any given biophysical study is to the know answers to basic questions such as, domain organization (in-silico analysis), purity (SDS, IEF, SEC), solubility and aggregation state, enzymatic activity, pH optimum and pI, temperature optimum, to name a few.
The aim of the lecture will be to sensitize the students for the topic by addressing a few important aspects such as the Hofmeister series and the solubility phase diagram, themes that are often neglected or underestimated.
Primers