D-Galactose

Absorption

The absorption of galactose from the human jejunum was calculated to be 1.0 g per minute per 30 cm of the gut .

Toxicity

It is typically uncommon to experience an overdosage situation with dietary galactose or from galactose as an ingredient in a therapeutic agent. At the same time, the experiencing a situation characterized by excessive amounts of galactose in the body defines the challenge with galactosemia, which is itself a rare genetic metabolic disorder. In individuals with galactosemia, the enzymes needed for further metabolism of galactose (ie. such as galactose-1-phosphate uridyltransferase) are severely diminished or missing entirely, leading to toxic levels of galactose 1-phosphate in various tissues . This toxic excess typically results in hepatomegaly, cirrhosis, renal failure, cataracts, vomiting, hypoglycemia, lethargy, brain damage, and ovarian failure . Without treatment, mortality in infants with galactosemia is about 75% .

Description

D-Galactose is a monosaccharide sugar that serves as an energy source and glycosylation component. It is a C-4 epimer of glucose and often used as a source of carbon in culture media. Galactose is a component of the disaccharide lactose and released upon hydrolysis by β-galactosidase enzymes. It is converted to glucose via the Leloir pathway or metabolized via an alternative pathway, such as the DeLey-Doudoroff pathway.

The Uses of D-Galactose

D-Galactose is suitable for use in cell culture systems requiring sugar additives.

Background

Galactose has been used in trials studying the treatment and diagnosis of Hepatitis C, Hepatic Cancer, Wilsons Disease, Diabetic Macular Oedema, and Focal Segmental Glomerulosclerosis, among others. There are even proposals for its use in accelerating senescence in mice, rats, and Drosophila, for its association with ovarian cancer, or even for the potential treatment of focal segmental glomerulosclerosis. Nevertheless, none of these ongoing studies have yet provided formal elucidation for their proposals.
As a naturally occurring sugar, it may be found in a number dairy products. Even then, however, it is not generally used as a sweetener considering it is only about 30% as sweet as sucrose. Regardless, although it is predominantly used as a pathway to generate glucose fuel for the human body, galactose is involved as an ingredient in some commonly used vaccines and non-prescription products.

Indications

There are limited therapeutic uses for which galactose is formally indicated. Some predominant indications include (a) the use of galactose to facilitate the construction of structurally and immunologically effective attenuated vaccines , and (b) the role galactose plays as an essential element in the formation of lactulose - a synthetic disaccharide indicated for the treatment of constipation and/or hepatic encephalopathy (HE); hepatic coma .
Nevertheless, there are many studies looking into a variety of possible uses for galactose, including the use of the monosaccharide sugar for accelerating senescence in mice, rats, and Drosophila , the proposed association between galactose in consumed milk and ovarian cancer , a possible role in the therapy of focal segmental glomerulosclerosis , among various others. Regardless, none of these proposed indications have yet been formally elucidated for practical use.

What are the applications of Application

D-Galactose is the C-4 epimer of glucose

Pharmacokinetics

Galactose is a naturally occurring monosaccharide that forms the disaccharide lactose when combined with glucose (another monosaccharide) . Subsequently, when lactose or small amounts of free galactose found in various common dairy products (and other foods) are consumed, the hydrolysis of lactose to glucose and galactose occurs and galactose is itself further metabolized to generate glucose . Such glucose is, of course, ultimately relied upon and used as the primary metabolic fuel for humans in a variety of biological reactions.
Conversely, however, the ways in which galactose is commonly used in therapeutic agents generally do not rely upon such pharmacodynamics, even though they ultimately remain the most important ways in which galactose exerts or elicits useful biological actions for the human body.

Metabolism

The primary pathway for galactose metabolism is called the Leloir pathway, so named after Luis Federico Leloir. The initial stage of this pathway is the conversion of beta-D-galactose to alpha-D-galactose by the enzyme galactose mutarotase (GALM) . The pathway then performs the conversion of alpha-D-galactose to UDP-glucose by way of three principal enzymes and their reactions: galactokinase (GALK) phosphorylates alpha-D-galactose to galactose-1-phosphate (Gal-1-P); galactose-1-phosphate uridyltransferase (GALT) transfers a UMP group from UDP-glucose to Gal-1-P to form UDP-galactose; and finally, UDP galactose-4-epimerase (GALE) interconverts UDP-galactose and UDP-glucose, which completes the pathway .