Preservative Effect of Polyols on the Stability of Biocatalysts during Short-term Dehydration Stress

Abstract

The preservative effects of different types of polyhydroxyl compounds on the stability of biocatalysts, β-amylase, pyruvate kinase and heat shock proteins, under dehydration stress were investigated. Polyhydroxyl compounds used in the present study were trehalose, sucrose, raffinose, maltose, lactose, glucose, glycerol, and dimethyl sulfoxide. The enzymatic activity of β-amylase was lost following both freeze-drying and air-drying; that of pyruvate kinase was lost only after air-drying. Non-reducing sugars, including trehalose, sucrose, and raffinose had marked preservative effects on the stability of these two biocatalysts. In contrast, glycerol caused the deterioration of their enzymatic activities. To our surprise, however, glycerol effectively retarded the inactivation of heat shock proteins, GroEL and Hsc73, caused by short-term dehydration. These findings are of considerable significance for understanding the interplay between heat shock proteins and the stress-induced accumulation of glycerol in anhydrobiotic organisms. Moreover, the utilization of non-reducing sugars as well as glycerol for storage of food materials and certain specific biocatalysts has been elucidated.