Elementary plant Biochemistry and Biotechnology (2+1)

Reducing disaccharides

Maltose

• Maltose is a disaccharide made up of two glucose residue joined by a glycosidic linkage between C-1 of one glucose residue and C-4 of the other. The configuration of the anomeric carbon of glucose involved in the linkage is œand hence the glycosidic linkage is α (1→ 4). The anomeric carbon atom of the second glucose is free and therefore maltose is a reducing sugar.The second glucose residue is capable of existing in α or ß configuration. Maltose has been recorded occasionally in plants. It is usually obtained as a product of the enzyme hydrolysis of starch during germination or malting process


Lactose

• Lactose is a reducing disaccharide found only in milk.It is made up of galactose at the non-reducing end and glucose at the reducing end.They are connected by a ß (1→ 4) linkage