Cellobiose

Cellobiose is a disaccharide consisting of two β-D-glucose units linked by a β-(1→4) glycosidic bond. Its systematic name is 4-O-β-D-glucopyranosyl-D-glucopyranose and its molecular formula is C12H22O11 (molar mass ~342.3 g/mol). It is a reducing sugar, with the anomeric carbon of the terminal glucose remaining free.

Biologically, cellobiose is derived from the enzymatic breakdown of cellulose. It is produced when cellulases cleave cellulose chains and is commonly present in cellulose-rich materials undergoing degradation. In nature, it serves as an intermediate that can be further hydrolyzed to glucose.

Physical and chemical properties: Cellobiose is a white, crystalline solid that dissolves readily in water. It is less sweet than sucrose. It is relatively stable at neutral pH but can be hydrolyzed by acid or by specific enzymes such as β-glucosidase or cellobiohydrolases.

Metabolism and applications: In organisms, cellobiose is cleaved by β-glucosidases to yield glucose for metabolism. In research and industry, it is used as a substrate to study cellulases and related enzymes, and can be used in enzymatic synthesis of oligosaccharides. It also serves as a standard substrate for enzyme assays measuring cellulase activity.