The progressive hydrolysis of the α(1 → 4) glucosidic bonds of amylose is catalyzed both by α-amylase and by β-amylase. With α-amylase the newly formed reducing group has the same αconfiguration...

The progressive hydrolysis of the α(1 → 4) glucosidic bonds of amylose is catalyzed both by α-amylase and by β-amylase. With α-amylase the newly formed reducing group has the same αconfiguration (before mutarotation) as the corresponding linkage in the polymer, whereas with βamylase it has the β-configuration. Suggest reasonable mechanisms for the two group-transfer reactions that would account for these observations.