α(1→2)β Glycosidic Bond

Definition

The α(1→2)β glycosidic bond is a type of covalent linkage that connects two monosaccharide units in disaccharides. It is characterized by the orientation of the anomeric carbon and the position of the glycosidic oxygen atom between the two sugar residues.

5 Must Know Facts For Your Next Test

1. The α(1→2)β glycosidic bond is found in the disaccharide sucrose, which is composed of glucose and fructose.
2. The α configuration of the glycosidic bond means that the hydroxyl group on the anomeric carbon is in the axial position, while the β configuration indicates that the hydroxyl group is in the equatorial position.
3. The 1→2 designation refers to the positions of the two monosaccharides involved in the glycosidic bond, where the anomeric carbon of one sugar is linked to the second carbon of the other sugar.
4. The α(1→2)β glycosidic bond is relatively stable and resistant to hydrolysis, contributing to the long-term storage of energy in sucrose.
5. The presence of the α(1→2)β glycosidic bond in sucrose is important for its functional properties, such as its sweetness and its ability to crystallize.

Review Questions

• Explain the significance of the α(1→2)β configuration in the glycosidic bond of sucrose.
  • The α(1→2)β configuration of the glycosidic bond in sucrose is significant because it determines the spatial arrangement and stability of the disaccharide. The α configuration of the anomeric carbon on the glucose unit means that the hydroxyl group is in the axial position, while the β configuration on the fructose unit places the hydroxyl group in the equatorial position. This specific arrangement contributes to the relatively stable nature of the glycosidic bond, making sucrose resistant to hydrolysis and suitable for long-term energy storage in the body.
• Describe how the α(1→2)β glycosidic bond in sucrose differs from other types of glycosidic bonds found in disaccharides.
  • The α(1→2)β glycosidic bond in sucrose is distinct from other glycosidic bonds in disaccharides, such as the α(1→4) bond in maltose or the β(1→4) bond in lactose. The α(1→2)β configuration, with the anomeric carbon of one sugar linked to the second carbon of the other sugar, results in a unique spatial arrangement and chemical properties. This specific bond type contributes to the functional characteristics of sucrose, including its sweetness and crystallization behavior, which differ from the properties of other disaccharides with alternative glycosidic bond configurations.
• Evaluate the role of the α(1→2)β glycosidic bond in the metabolism and utilization of sucrose within the human body.
  • The α(1→2)β glycosidic bond in sucrose plays a crucial role in its metabolism and utilization within the human body. The relative stability of this bond, compared to other glycosidic linkages, allows sucrose to be efficiently absorbed and transported in the digestive system. Once absorbed, the glucose and fructose moieties can be metabolized separately, with glucose providing a readily available source of energy and fructose being converted to glycogen or other metabolic intermediates. The specific bond configuration also contributes to sucrose's functional properties, such as its sweetness, which can influence food preferences and dietary intake. Overall, the α(1→2)β glycosidic bond is a key structural feature that enables the efficient metabolism and utilization of sucrose as a valuable energy source and dietary component.

Related terms

Glycosidic Bond:

A covalent bond that connects a carbohydrate (sugar) molecule to another group, such as another sugar, a lipid, or a protein.

Anomeric Carbon:

The carbon atom in a monosaccharide that is attached to two oxygen atoms, one of which is part of the ring structure and the other is the glycosidic oxygen.

Disaccharide:

A type of carbohydrate composed of two monosaccharide units linked together by a glycosidic bond.