Trehalose-enzyme interactions result in structure stabilization and activity inhibition. The role of viscosity.

Stress resistance is essential for survival. The mechanisms of molecule stabilization during stress are of interest for biotechnology, where many enzymes and other biomolecules are increasingly used at high temperatures and/or salt concentrations. Diverse organisms, exhibit rapid synthesis and accumulation of the disaccharide trehalose in response to stress. Trehalose is also rapidly hydrolyzed as soon as stress ends. In isolated enzymes, trehalose stabilizes both, structure and activity. In contrast, at optimal assay conditions, trehalose inhibits enzyme activity. A general mechanism underlying the trehalose effects observed at all temperatures probably is the trehalose-mediated increase in solution viscosity that leads to protein domain motion inhibition. This may be analyzed using Kramer's theory. The role of viscosity in the effects of trehalose is analyzed in examples from the literature and in studies on the plasma membrane H(+)-ATPase from Kluyveromyces lactis. In the cell, it may be proposed that the large concentration of trehalose reached during stress stabilizes structures through viscosity. However, once stress ends trehalose has to be rapidly hydrolyzed in order to avoid the viscosity-mediated inhibition of enzymes.