Reaction mechanism of a new glycosyltrehalose-hydrolyzing enzyme isolated from the hyperthermophilic archaeum, Sulfolobus solfataricus KM1

Amylolytic activity, which converts soluble starch to alpha,alpha-trehalose (trehalose), was found in the cell homogenate of the hyperthermophilic acidophilic archaeum, Sulfolobus solfataricus KM1. Two enzymes, a glycosyltransferase and an alpha-amylase, which were essential for this activity were identified, The alpha-amylase was purified to homogeneity on SDS-PAGE, The alpha-amylase catalyzed the hydrolysis of glycosyltrehaloses to trehalose, Analysis of the reaction products, kinetic parameters, and experimental findings using H-3-labeled substrates indicated that the alpha-amylase hydrolyzed only the alpha-1,4 glucosidic linkage adjacent to the trehalose unit of the glycosyltrehaloses, Six strains of the Sulfolobaceae family examined were observed to have the glycosyltrehalose-hydrolyzing enzyme, the alpha-amylase.