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-treh alose (trehalose), was found in the cell homogenate of the hyperthermo philic 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 homog eneity on SDS-PAGE, The alpha-amylase catalyzed the hydrolysis of glyc osyltrehaloses to trehalose, Analysis of the reaction products, kineti c parameters, and experimental findings using H-3-labeled substrates i ndicated that the alpha-amylase hydrolyzed only the alpha-1,4 glucosid ic linkage adjacent to the trehalose unit of the glycosyltrehaloses, S ix strains of the Sulfolobaceae family examined were observed to have the glycosyltrehalose-hydrolyzing enzyme, the alpha-amylase.