1,4 glycosidic bonds
A 1,4-glycosidic bond is a covalent bond between the -OH group on carbon 1 of one sugar and the -OH group on carbon 4 of another sugar. This is a condensation reaction as a molecule of water is released. It can be broken by consuming a molecule of water in a hydrolysis reaction.1 The bond can either be in the α or β form depending on the position of the hydroxyl group on the carbon 1 involved in the bond. The α-1,4-glycosidic bond has the hydroxyl group pointing down. The β-1,4-glycosidic bond has the hydroxyl group pointing up.2 1,4-glycosidic bonds can be found in both amylase and amylopectin in glycogen. These linkages create branching in the polysaccharide. Amylopectin and amylase are both readily hydrolysed by the α-amylase enzyme.3
1-Bruce, A., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008). Molecular Biology of the Cell. 5th ed. New York: Garland Science. 56-57.
2-Bruce, A., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008). Molecular Biology of the Cell. 5th ed. New York: Garland Science. 113.
3-Berg JM, Tymoczko JL, Stryer L. (2002). Biochemistry. 5th ed. New York: W H Freeman. Section 11.2.2.