Regional distant sequence homology between amylases, α-glucosidases and transglucanosylases

AbstractAmylases possess short, conserved regions near functional side chains. Sequence comparison extends this relationship to comprise a maltase and a cyclodextrin glucanotransferase. Similarity also exists with intestinal sucrase-isomaltase and fungal glucoamylase near identified essential carboxyl groups. Homology between COOH-terminal regions of glucoamylase and cyclodextrin glucanotranserase may indicate raw-starch binding areas. It is suggested that amylases, α-glucosidases, and transglucanosylases acting on 1,4- and 1,6-α-glucosidic linkages share key structural features in the active centres