Assessing The Value Of Temperature Control On Centrifugal Vacuum Concentration

Temperature effects are the nemesis of researchers doing protein purification. The heterogeneous nature of each protein species renders it with inherent characteristics that make potential temperature fluctuations a hazard to that protein’s stability. Indeed it is well know that high temperatures can cause denaturation, as well as freezing, but some proteins are even sensitive to low temperatures in that they are cold labile. Consequently when working with new biological extracts with the aim of protein purification, loss of activity may result from the traditional practice of chilling the sample.

A common technique used in protein purification is vacuum concentration. Gel filtration fractions and dilute extracts can be easily concentrated by the removal of water using products such as the Labconco CentriVap Centrifugal Concentrator. Samples are placed in the vacuum concentrator and centrifuged while a vacuum is applied. The centrifugation prevents the sample from splattering from tubes or microwell plates as a result of the pressure decrease. Under moderate vacuum, heating and cooling of the sample are also possible with the Labconco Refrigerated CentriVap. As noted below, temperature control can have an important impact on sample integrity.

Many samples which are vacuum concentrated contain inert or resilient solutes, as with inorganic ions or non-volatile organics. However, most biomolecules are susceptible to some type of degradation during processing. Major hazards are caused by proteases and nucleases which attack molecules in fresh lysates. Inhibitors can be used to suppress most enzymatic degradation, but a risk still exists that some of the desired biomolecules will be lost. Typically a combination of inhibitors and temperature control are used while manipulating samples. Using a temperature regulated centrifugal concentrator, such as the Refrigerated CentriVap, protection of biomolecules during vacuum concentration is also possible.