alpha14glycosidic

Alpha-1,4 glycosidic bond, sometimes written alpha-1,4 glycosidic linkage, is a covalent bond that connects the anomeric carbon (C1) of one α-D-glucose unit to the hydroxyl group on C4 of the adjacent glucose unit, with the linkage in the alpha configuration. This bond forms the main chain in many storage polysaccharides and is non-reducing at the end of each internal linkage, contributing to the overall structure of the polymer.

This type of linkage is prevalent in starch and glycogen. In starch, it appears in the linear polymer amylose and in the branched polymer amylopectin, where alpha-1,4 bonds create long glucose chains and alpha-1,6 bonds introduce branching. Glycogen uses a similar pattern but with more frequent branching, yielding a highly soluble and readily mobilized storage polysaccharide. The alpha-1,4 linkage imparts a helical or compact arrangement to these polymers, influencing their physical properties such as gelatinization, solubility, and digestibility.

Enzymatically, alpha-1,4 glycosidic bonds are hydrolyzed by digestive enzymes like alpha-amylase, which cleaves the bonds to produce smaller sugars such as maltose and maltotriose, and ultimately glucose. In contrast, beta-1,4 glycosidic bonds—found in cellulose—form straight chains that are not digestible by human enzymes.

In disaccharides, maltose consists of two glucose units linked by an alpha-1,4 bond. The term alpha-1,4 glycosidic bond is a fundamental concept in carbohydrate chemistry, relevant to nutrition, biochemistry, and food science.