Thermostable

Thermostable describes a molecule, formulation, or organism that maintains structural integrity and function at elevated temperatures. In biochemistry and biotechnology, thermostability refers to a protein or enzyme retaining folding and catalytic activity after exposure to heat beyond what is typical for its source.

Measurement of thermostability commonly uses metrics such as melting temperature (Tm), determined by differential scanning calorimetry or differential scanning fluorimetry, and a protein’s half-life or residual activity after heating. These measures help compare stability across variants and conditions.

Thermostability arises from structural features and can be enhanced by various engineering approaches. Factors include increased core packing, more salt bridges and hydrogen bonds, disulfide bonds, shorter surface loops, and oligomerization that reduces unfolding. Engineering strategies encompass directed evolution, consensus design, and rational mutations to rigidify regions, stabilize interfaces, or introduce stabilizing interactions.

Applications are broad. Thermostable enzymes enable industrial biocatalysis, high-temperature processes, and robust performance in detergents and biofuel production. In molecular biology, thermostable polymerases enable PCR by withstanding repeated heating cycles. In global health, thermostable vaccine formulations aim to reduce cold chain dependence, improving distribution in resource-limited settings.

Limitations and trade-offs exist. Increasing thermostability can sometimes reduce catalytic efficiency, alter substrate specificity, or compromise expression and folding. Consequently, stabilizing a protein or formulation requires balancing stability with functional and practical considerations.