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

Abstract

Amylases 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.