Exploring enzymatic activity in multiparameter space: cosolvents, macromolecular crowders and pressure

Abstract

The use of cosolutes and high hydrostatic pressure has been described as an efficient means to modulate the stability of enzymes and their catalytic activity. Cosolvents and pressure can lead to increased reaction rates without compromising the stability of the enzyme. Inspired by the multi-component nature of the crowded cellular milieu of biological cells of piezophiles, we studied the combined effects of macromolecular crowding agents, different types of cosolvents and pressure in concert on a hydrolysis reaction catalyzed by α-chymotrypsin. We have seen that crowding agents and cosolvents can have very diverse effects on enzymatic activity. Addition of the deep-sea osmolyte trimethylamine-N-oxide displays by far the most positive effect on the catalytic efficiency, keff, of the reaction, which is even markedly enhanced at high pressures. Addition of the chaotropic agent urea leads to the reverse effect, and PEG and dextran as two representative crowding agents of a different nature show nearly similar values for keff compared to the pure buffer data. Such information may not only be relevant for understanding life processes in extreme environments, but also for the use of enzymes in industrial processing, which often requires harsh conditions as well.