laminaribiose

Laminaribiose is a disaccharide consisting of two β-D-glucose units linked by a β-1,3-glycosidic bond, i.e., β-D-glucopyranosyl-(1→3)-β-D-glucopyranose. It has the molecular formula C12H22O11 and is a reducing sugar because one anomeric carbon remains free at the reducing end.

Natural occurrence and formation: Laminaribiose occurs as a breakdown product of β-1,3-glucans such as laminarin, a storage polymer in brown algae. It is formed by enzymatic or chemical hydrolysis of laminarin and related β-1,3-glucans. It can be isolated from laminarin hydrolysates or prepared synthetically.

Enzymology and metabolism: Enzymes that act on the β-1,3 linkage include β-1,3-glucanases and other β-glucosidases; hydrolysis of laminaribiose yields two glucose molecules. In laboratory settings laminaribiose serves as a model substrate for studying β-1,3-glucan metabolism and for assaying β-1,3-glucan-degrading enzymes.

Applications and notes: Laminaribiose is used as an analytical standard in carbohydrate analysis and as a substrate in enzymatic assays to probe β-1,3-glucanases. It also serves as a component in studies of brown algal polysaccharides and their digestion.