Depending on whether the glycosidic bond lies "below" or "above" the plane of the cyclic sugar molecule, glycosides are classified as α-glycosides or β-glycosides. Some enzymes such as α-amylase can only hydrolyze α-linkages; others, such as emulsin, can only affect β-linkages.
There are four type of linkages present between glycone and aglycone:
* C-linkage/glycosidic bond, "nonhydrolysable by acids or enzymes"
* O-linkage/glycosidic bond
* N-linkage/glycosidic bond
* S-linkage/glycosidic bond