D-Galactose
[CAS# 59-23-4]

Identification

• Classification: Biochemical >> Carbohydrate >> Monosaccharide
• Name: D-Galactose
• Molecular Formula: C₆H₁₂O₆
• Molecular Weight: 180.16
• CAS Registry Number: 59-23-4
• EC Number: 200-416-4
• SMILES: C([C@H]([C@@H]([C@@H]([C@H](C=O)O)O)O)O)O

Properties

• Solubility: 100 mg/mL (water)
• Density: 1.5 g/mL
• Melting point: 165-168 °C
• alpha: 80

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319-H335
• Safety Statements: P261-P264-P270-P271-P280-P301+P312+P330-P302+P352-P304+P340+P312-P305+P351+P338-P332+P313-P337+P313-P362-P403+P233-P405-P501

Discovery and Applications

D-galactose is a monosaccharide and the C-4 diastereomer of glucose that was first isolated and identified in the early 20th century. Its discovery stemmed from studies of lactose hydrolysis, when it was found to form the disaccharide lactose together with D-glucose. Structurally, D-galactose has a six-carbon chain with an aldehyde group (CHO) on the first carbon and a hydroxyl group (-OH) on the fourth carbon, differing from glucose by the position of the hydroxyl group on C-4.

In biological systems, D-galactose plays several important roles: It is primarily metabolized in the liver via the Leloir pathway, involving enzymes such as galactokinase, galactose-1-phosphate uridyltransferase (GALT), and UDP-galactose 4-epimerase. This pathway converts D-galactose to glucose-1-phosphate, which is used for energy production or glycogen synthesis. D-galactose is a component of cell surface glycoproteins, glycolipids, and glycosaminoglycans. These structures play important roles in cell-to-cell recognition, signaling, and immune responses.

D-galactose is used in clinical diagnostics to assess liver function. The galactose challenge test assesses liver function by measuring the body's ability to metabolize D-galactose. Impaired metabolism indicates liver dysfunction. In biomedical research, D-galactose is used to induce aging models in experimental animals. Long-term administration of D-galactose can mimic oxidative stress and accelerate aging-related changes in various organs.

D-galactose and its derivatives are used as sweeteners and flavor enhancers in food processing. They contribute to the taste of dairy products, and they occur naturally in lactose. D-galactose derivatives are building blocks for the synthesis of complex carbohydrates and pharmaceuticals. Its role in the glycosylation process is essential for the creation of bioactive compounds and vaccines.

Galactosemia is a genetic disorder caused by a deficiency in GALT enzyme activity, resulting in the accumulation of galactose in tissues. This condition requires strict avoidance of galactose-containing foods, including dairy products, to prevent serious health complications.

Research continues to explore the role of D-galactose in the mechanisms of aging and oxidative stress. Animal models using D-galactose provide insights into neurodegenerative diseases, cardiovascular diseases, and metabolic syndrome associated with aging.

References

1979. Galactosemia: Alterations in Sulfate Metabolism Secondary to Galactose-1-Phosphate Uridyltransferase Deficiency. Science (New York, N.Y.), 205(4413).
DOI: 10.1126/science.472754

2024. κ-Carrageenan Hydrogels as a Sustainable Alternative for Controlled Release of New Biodegradable Molecules with Antimicrobial Activities. Journal of Polymers and the Environment, 32(8).
DOI: 10.1007/s10924-024-03189-6

2023. Synthesis and pharmacological evaluation of novel coumarin based triazolyl glycoconjugates as potential antibacterial and anti-proliferative agents. Medicinal Chemistry Research, 33(2).
DOI: 10.1007/s00044-023-03178-9