Suppression of protein inactivation during freezing by minimizing pH changes using ionic cryoprotectants
| Authors | |
|---|---|
| Year of publication | 2016 |
| Type | Article in Periodical |
| Magazine / Source | International Journal of Pharmaceutics |
| MU Faculty or unit | |
| Citation | |
| Web | |
| Doi | http://dx.doi.org/10.1016/j.ijpharm.2016.05.031 |
| Field | Pharmacology and pharmaceutical chemistry |
| Keywords | Protein cryopreservation; Freezing/thawing; Protein aggregation; Protein stability; Quality by design; Freezing stress; Freezing-induced pH shift |
| Description | Freezing and lyophilization are often used for stabilization of biomolecules; however, this sometimes results in partial degradation and loss of biological function in these molecules. In this study we examined the effect of freezing-induced acidity changes on denaturation of the model enzyme haloalkane dehalogenase under various experimental conditions. The effective local pH of frozen solutions is shown to be the key causal factor in protein stability. To preserve the activity of frozenthawed enzymes, acidity changes were prevented by the addition of an ionic cryoprotectant, a compound which counteracts pH changes during freezing due to selective incorporation of its ions into the ice. This approach resulted in complete recovery of enzyme activity after multiple freeze-thaw cycles. We propose the utilization of ionic cryoprotectants as a new and effective cryopreservation method in research laboratories as well as in industrial processes. |
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