Protein Stabilization

For many industrial processes, biocatalysts provide a desirable specificity not possible with either the analogous uncatalyzed chemical reaction or a catalyzed nonenzymatic counterpart. For example, in the conversion of starch to high-fructose corn syrup, α-amylase consistantly yields a product containing 3–5% more dextrose than simple acid hydrolysis, with less impurities and by-products.1 Similarly, rennin (chymosin) is used in the making of cheese because it will specifically cleave only the κ-casein component in milk thus initiating the clotting process.2 The use of biocatalysts however remains limited, because while many applications require harsh conditions (such as temperatures greater than 50 °C) to ensure high productivity, high solubility of substrates, and reduced microbial contamination, these conditions often result in an irreversible inactivation of the enzyme.3 Hence repetitive, time-consuming additions of the costly catalyst are necessary to maintain the process. This dilemma has compelled scientists to search for means to stabilize biocatalysts against irreversible inactivation.