SpectroLight 600/610

Buffer screening

Buffer screening depends on the reversibility of aggregate formation due to low solubility. Most proteins tend to assemble into soluble aggregates when stored in an inappropriate buffer and can be resolubilised when the surrounding buffer is changed. Thus, the overall folding is often still intact. Therefore, the basic aim of buffer screening is to break up such aggregates and keep the proteins separated from each other. Evaluating whether optimal buffer conditions have been achieved has always been a bottleneck. However, the two parameters that DLS can reveal: “particle size” and “dispersity” are sufficient for evaluation. There are several negative influences that affect the overall 3D folding of a protein and ultimately force it into an aggregated state. These include positive surface interactions, low solubility due to exposed hydrophobic moieties, chemical degradation, heat-induced unfolding, catalytic degradation by protease activity and autocatalytic digestion. Each of these factors forces a protein into a state of aggregation that can be detected by DLS. Proteins therefore have a characteristic size distribution signature when dissolved in the right or wrong buffer. A well-formulated protein is stable, i.e. the size and dispersion remain constant.

 

 

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